Tim Sweeney
Appearances
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But you can determine the economic correlation between a game mode and spending.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, I think so. You don't need an alternate currency system. Unfortunately, a bunch of ideas have been conflated because people are trying to hype up different things, but this idea of large-scale multiplayer social gaming, that notion of the metaverse, there's 600 to 800 million people playing that kind of game every month.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So you know that's real and that's happening, and it's very much underway. VR has a much smaller audience. I don't think you need VR to have anything like this. VR is hardware that may or may not enhance the experience for some usage cases. For some, it will probably be better, and for some, it will probably be worse. But certainly, there's not any set of Battle Royale players flocking to VR
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
talking to VR. And the other thing is an FT is it's like, you know, trying to equate digital or cryptocurrency to, to the metaverse. It's like, well, you know, It's just a way of denoting money or value exchange. You can do that with money or you can do it with NFTs or whatever. But there's nothing about this future digital economy that fundamentally requires cryptocurrency or whatever.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
What you need is interoperability. Interoperability can happen through a blockchain. It can happen through a database. It can happen through standards bodies, defining standards and protocols. And we've been doing it for hundreds of years since the railroads were standardized. And It's not something that totally requires a novel technological solution.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, people often go to university and think, okay, my goal here is to get good grades so I get a diploma and I prove to an employer that I'm valuable. Like, no, that's just kind of the superficial bookkeeping of the university. The real purpose of all of this is to learn. And whether you learn formally or you learn on your own, it's the learnings that are really valuable in a career.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We need a lot of different things. The one area where the standards bodies have been very successful in creating working standards implemented by all the major engines today is in low-level file formats for data interchange. The web has PNG files for 2D images. and MP3 files for audio.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And 3D has the Pixar USD file format, the Universal Scene Description, which is a description of the scene graph, the entire set of objects in the scene and all of their parameters so that any engine that supports those features could import that and then render the same scene as the engine they came from.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, large parts of this work across Unreal Engine and Unity and Blender and all of these 3D packages of different sorts. Then there's the glTF texture format, which stores textures and geometry and other low-level data for 3D objects.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
When you see a Fortnite character, that file format together with the image file formats can store their static appearance, the shape of their body, even their animations and their different poses, and the appearance of them. The different standard file formats could store all the sounds they make in their emotes, but we're still missing a bunch of pieces.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And especially if you're going to be an entrepreneur, it's really knowing the stuff that matters and not having the diplomas and to... There's ever more pressure to rebuild society, more and more around credentials. Do you have this certificate? Do you have that proof?
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The biggest missing piece is the programming language that's at the center of standardizing the Matterverse. Now, if you look at the web, the web is a combination of a bunch of different technologies. The two biggest ones are HTML, which describes... the 2D scene graph, or the 2D layout of controls and objects on the web page. But that's just static data.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's just a non-moving, non-animating web page. And then you have the JavaScript programming language, which is used to manipulate that, to display things to the user, and to implement anything you could implement in code. So it's a little programming language that runs in your web browser. And the metaverse needs something that performs that similar role.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But the metaverse and 3D gaming in general needs something that's rather more powerful, more safe, more scalable, and more capable than JavaScript. Because the metaverse is actually a more difficult technical problem than a web page. A web page, like an app, is just a single bundle of... code and content that somebody, a company, has prepared.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And they release it, and it stays exactly what it is until they release a new version, and it's upgraded from version to version as it goes. But the metaverse needs to be a composite of code and content built by millions of different people that could potentially form a seamless world together.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, the highest detail of Fortnite updates amount to about 60 gigabytes of data. And, you know, that's just a small part of what exists in the Fortnite creative economy. And if you look at what this might be in a decade as standards emerge, you might have exabytes of data out there. Fortnite Battle Royale is, I don't think, the ultimate manifestation of gameplay that will ever be invented.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
What we've seen time and time again is that as... We gain more technical capabilities. Graphics gets more capable. CPUs become more performant. Web services become ever more scalable. We see new genres of games that emerge that weren't possible before. And, you know, Doom ushered in the era of Deathmatch, the first time 3D multiplayer game was even possible at all.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But companies that are focused on just building great products and doing great things gravitate towards people who do the great work.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The early Battle Royale games, starting about 10 years or 15 years ago, only became possible back then. You couldn't have built one 20 years ago, because you just couldn't have rendered an environment that's as large as a VR game with that many players, with that level of interaction and performance. It was just not possible to run it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So you got a certain level of technical capabilities, and a genre came out that proved to be by far the best shooter genre ever invented. But I think there are numerous, numerous more genres, some of which are better than any of the existing ones that will be invented as we get more and more capabilities.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Some of the capabilities we're lacking now are the ability to build environments and game simulations that span... more work than a single company can possibly create. And, you know, you see kind of the birth of that idea in Fortnite and Roblox, where there are tens of thousands of creators each building content, and users are playing meaningful amounts of it all.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so there's an ecosystem that's scaled larger than company. But it's still very much, you go into one island and you play that creator's work. The other direction of scalability is putting more and more of people's work together in a seamless, continuous play space for games where that makes sense. You know, you can imagine a...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
a game taking place in an environment that's the size of a continent or Earth, in which you can go from place to place and see different areas which are maintained by different people. So you go into different spaces, the game rules are customized according to that, and you can go from experience to experience.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And instead of having just one company's authorship ever-present wherever you are, you'd be driving a car built by one person, carrying weapons built by 20 other people, and taking place in a simulation in an environment that's built by thousands of other people, working for separate companies or their own entrepreneurs or... indies or enthusiasts all working together simultaneously.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And we totally lack the programming foundations for that. The kinds of code you would need to write now to make that happen are just not practical. And so we're investing massively in building new programming language technologies around Verse and our proposed standards for future metaverse programming that we hope will solve those kinds of problems and make that kind of world possible.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
First is the programming language that we're building for large-scale simulation programming. It's designed to make it easy to write code that can scale up to not only you building a Fortnite island, but you building modules or components that can be used by millions of other programmers and coexist in a huge environment, and also can scale up to a huge-scale simulation. Some games will be small.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Battle Royale might find that 100 players is actually optimal. It might be the 1,000-player version of Battle Royale would be worse. But I bet there are 1,000 million and tens of million player experiences that are even better than that that will yet to be discovered. Wait a minute.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Sure, we've had Fortnite events that have attracted 15 million concurrent users, but the fact that they're all divided up into servers with 100 players each for those events isn't really a positive. It's just a limitation of the technology. tracing back to Unreal Engine 1 and its single threading decisions.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If we could build a concert where all the concert participants, potentially tens of millions of them, could participate together simultaneously and see that there's that massive crowd and they could all do interesting things and interact with each other, that would be way cooler.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Sure. Well, you know, 10 million people. You have less than 10 million pixels on your screen. So as the Nyquist sampling theorem say, it says that you don't need full overhead for every player. You need to render the players here around you in some approximation of everything else.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's a lot of work that has to happen there, but this is what we do for a living. We solve hard problems.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Because if they're easy, then other people could have solved them already.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
versus a functional logic language, because we think that that's the way to make the most simple and powerful language simultaneously. Back in the 1970s, the programming language designer who built Pascal
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
One of the early programming languages, Niklaus Wirth, or Nicholas Wirth, as Americans might call him, stated this principle that a programming language should achieve a high degree of power, not by having a lot of features, but by having a small number of features that work together and can be composed together arbitrarily.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So that you have to learn a relatively small set of things, and then the real knowledge comes as you learn ways to combine them to achieve bigger and bigger programs. And so there's a long history to the field of programming languages, but in the 1950s, the first... programming language designers got together and built the first standardized language called ALGOL.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And there was this meeting in 1956. Very few people even know about it, but it's where all the major foundations of modern programming languages were decided on, that the C family of languages inherited. And so we're very much living in a world that was defined by them. And thankfully, they got a whole lot of things right.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They defined how functions should work, how variables should work, and how recursion should work. And thank God they got those things right. But they got a few things wrong. versus trying to fix those, and that's the functional logic part of it. The interesting thing about functional logic languages is that in an old-school language, an expression produces a value.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think this is something that's kind of changing in America. There's so much focus on grades and homework and structure around kids' lives. When I was growing up, my neighbors and moms would feed them breakfast, and they'd be like, well, be back by dark. Yeah. And, you know, we'd go out and we'd play and we'd do all sorts of things. We'd explore the woods. We'd build go-karts.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
In a functional logic language, an expression can produce zero, one, or multiple values. If it produces zero values, we might say it fails. If it produces one value, we say it succeeds. If it produces multiple values, it's kind of providing a set of values you could iterate over.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so there are a bunch of features in today's programming languages that were defined in an ad hoc way without really thinking this through, this zero, one, or many values way. And that's the problem that functional logic languages address. The most basic example is an if statement in a programming language. If some condition holds, then do this thing. Otherwise, do that thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And in the language today, this is done with variables of type Boolean or expressions that produce Booleans. We have Boolean variables that are either true or false. We have expressions that evaluate to Booleans. And so you can express a condition as a bunch of these features together But you've lost any computation you've done in doing that Boolean expression evaluation.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So in a functional logic language, your condition wouldn't do that. It would either succeed and produce a value, or it would fail. If it succeeds, it goes to the then branch. Your operation succeeded, now you're running this one batch of code. And if your expression failed, then you go to the else branch.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But the exciting thing about that is your expression that succeeds or fails can produce values and bind variables that are then accessed by the then branch. So you can write a conditional where you can only get to the inside of the condition, the then, if a bunch of variables have successfully been bound to variables.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So it lets you test if some conditions hold and then use the results of those tests. And that gives you a much higher level of reliability. And then a for loop... In a traditional language, it's just a bunch of imperative code that's woven together to produce a bunch of values iteratively.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's rather awkward to do complicated things in for loops, and so you often end up with the ever more complicated constructs built to work around that, like iterators and other things. The idea of functional logic languages is your for loop can just produce... multiple values.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And if it produces zero values, you got to reiterate zero iterations, and it produces a bunch of values, you got to do all those as your iterations.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Rather than having a bunch of nested loops, you can write arbitrary things that look like SQL queries in a condition or in a for loop that bind a bunch of variables, do a bunch of tests, produce a bunch of a series of results, and in some order that you're iterating over, and then you can handle all of them and produce result.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So you kind of gain the power of SQL queries, you know, large complex queries over data structures in a language that is much simpler in which your code is just performing simple iterative operations. And so kind of gives you the best of databases and of regular programming in a much more uniform way. And the power of this is now users can write functions that not only
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
produce a value, you can write functions that might fail. And so you can write a function that answers a question, the answer can be either yes, and my value is this or no. And you can combine these together into arbitrary And I feel like the funny thing is that this is not how C++ works.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so when we have epic programmers moving over from C++ and writing their first verse code, they try to write C++ code in verse style, and it actually ends up being kind of convoluted code that's worse than good C++ or good verse. But after a few months, they get up to speed, and they're writing really awesome code that's tighter and more compact than before.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And with users who've never programmed before but are learning programming for the first time in the context of Fortnite, it's really fascinating. You see, these users are learning this kind of as... It becomes their intuition. They just assume programming works this way.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And they're writing way more advanced and interesting for loops and conditions than we're often writing internally because they've kind of grokked the core concepts.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We'd salvage old pieces of electronics and build what we thought were our spacecraft control panels for the fake spaceships we were building as play. And we'd have an enormous amount of freedom. And, you know, from basically being a little kid through... through the time I went off to college, it had an enormous amount of free time. Some people just used that and wasted it and watched TV.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, right. So the challenge with the metaverse is, first of all, that it's a huge base of code that's evolving over time and written by many authors. You might see every second a new module is updated somewhere, and you expect in this live, ever-running simulation that never shuts down, for everything to upgrade live in place. And so one critical component that is the ability to
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
release an update to something you've already published and be sure that it's backwards compatible with the one that you've already released. And that's essentially a type checking problem, checking that your new interface is backwards compatible with your old one. And that comes down to the type system of the language.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's been a lot of very interesting research on type systems over the years, most of which hasn't ever made it into the C++ programming language, unfortunately. But you see several branches of that whole field.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
One of the really interesting things that Java and C Sharp did in the early days, and then later abandoned and didn't bother update, was defining a very rigorous set of rules for if you publish a module... with one set of types today, then what changes can you make to that module for your future updates to it that don't break backwards compatibility? And that's a problem for type checking.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Say you have a function that promises to return some integer. Well, in the future, you could say that returns some natural number, because every natural number is an integer. So that's a backwards compatible change. But you can't say it returns a rational number, because some rational numbers are not integers. So the system ought to reject that kind of change.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But the much, much, much more interesting thing about type checking was the realization, it was actually made in the 1930s, that if you design a programming language type system in a very particular way, then it becomes not only useful for expressing types of variables. The traditional thing every type system does is say, like, variable X is of type integer.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But if you design a type system in a certain way, then your types can express theorems, like mathematical theorems. You know, the Pythagorean theorem is a cool one. But one theorem you might set up in a program is like the theorem that this function takes an array of integers and returns an array of the same integers, but the result is sorted.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you express that as a theorem and you follow this system of type theory, then you can actually require that anybody who writes that sorting function to prove that it has actually sorted its result. And so you have types or theorems, and values constructed a certain way can be proofs of those theorems.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And nowadays in mathematical literature, you see more and more theorems are being proven mechanically. Mathematicians are proving theorems in a way that is verified by computer to be a correct proof. In the old days of math, people would write down language. If you look at all of Euclid's theorems, it was just language.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It was just writing in ancient Greek to say the steps of the proof to convince the reader that the thing is true. Starting in the 1930s, mathematicians moved towards rigorous formal proofs in which there's a series of steps that can be mechanically verified. They're proving things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And when mathematicians say they've done a computer proof of a theorem, what they really mean is they've written the program in a proof language, like Lean is a theorem prover, COQ is a theorem prover, and there are several others. It means they've written a mechanical proof in that language that a computer has checked so that... It's impossible to lie.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Some people socialized. And some people really got into serious projects. So many people at all times were doing cool things. I was programming. I was learning to build things. Before I was releasing games to the world, I'd be like... Having neighborhood folks over to play the things I was working on and check them out. Sometimes they're impressed, and sometimes they weren't.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you say that you've proven a thing and the computer verifies it, then it's definitely true. And this is a feature of mathematical proof languages, but it's also an idea that's making its way into programming languages gradually over time. And our aim for Verse is to be the first mainstream programming language that fully adopts that approach and that technique.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And not only adopts it, but it adopts it in a way that's really user-friendly, so you don't have to do that. And the idea of this is that you want gradually more information to be incorporated in the types of variables. The property you want of a programming language is that if your compiler accepts your program and doesn't beep and tell you there is an error, then your program should work.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Now, there are all kinds of ways humans can make mistakes there, so that we'll never achieve that ideal. But we can get closer and closer to it by having more and more language features that enable the compiler to catch more human coding errors and tell the user what went wrong. And that becomes extremely important in the metaverse.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The cost of fixing a bug that's made it through to runtime and is in users' hands, the cost of fixing a bug in a shipping program is hundreds of times higher than fixing a bug that you've just observed as you're running your code yourself. When it's running on your computer, you just fix a line of code, and your bug's fixed. When you have to fix it live, you have to release a patch.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You have to release patch notes. You have to test the patch. You have to check for all the other bugs that might have been introduced, and everything becomes vastly, vastly more expensive. So, you know, the real aim of the verse program and approach is to catch all of these errors at compile time and make the metaverse a very reliable place.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
proving things becomes combinatorially harder as they get larger, right? And so the really important thing about this whole field is that you should be able to adopt these capabilities gradually and apply it where you really need it. Like if you're writing something like a cryptography algorithm, that's a good place to prove stuff.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you're writing a data decompressor that's going to be used by an entire ecosystem, like proving that that doesn't overrun memory is actually really important. And a lot of the reason that security vulnerabilities happen today is because in a different language, a compiler could have caught. We're not caught in C because it just doesn't have this feature.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But yeah, we shouldn't see this as scary. Everybody working in a typed language like C or C sharp or Java is proving theorems all the time, if you have a variable of type integer and you assign some value to it, you've proven to the compiler that that value was an integer, because otherwise it would have rejected it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so as we add more and more advanced proofs, we'll get compositional properties falling out of our systems that are easy to use and people prefer to use.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If we might think in a future where we have AI helping us write certain kinds of code, the big problem with AI is you ask it to do something, ask you to write a fragment of code that does something, it might give you a perfectly valid fragment of code that compiles but does the wrong thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And if we had languages where you could say, write a function that sorts this array and prove that it did that, it could actually write the proof. And If the compiler didn't beep with it, you could trust that it was actually sorting the array. And otherwise, you could go back to the AI and say, well, that didn't work.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But getting to the point where we know that our programs do what we say they're going to do or think they're going to do is a very important thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They'd have their own projects. Often we'd have spare time jobs, and everybody was entrepreneurial. Everybody had a side gig. Sometimes you'd go around and mow people's lawns, or you'd rake the leaves up and earn money. There's freedom there. organic learning that occurred there, I think it's something that is really critical to the American experience.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's right. This is a result from the 1930s. It's one of the most important results of computer science that almost nobody knows about. But they did this rigorous breakdown of type systems and the 1930s formulation of programming and established that everything you can prove in mathematical logic, you can prove within a type system if it has certain features.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, if you break down what is a proof, well, a proof that integers exist is some integer. Like five is a proof that integers exist. So when you have, you know, something like var xint and you say x equals five, well, you're proving to the compiler that five is an integer. You know, that comes as a secondhand nature, but you can prove more advanced things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you want to prove that a pair of things are true, like theorem A is true and theorem B is true, then you need to provide a pair of values, one that proves theorem A and one that proves theorem B. And that's the conjunctive law of proofs. And there's a disjunctive law, too. And then there's an implication law for proofs. And it turns out that that's really satisfied by functions.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
When you write a function in a programming language, you're saying, if you give me this thing, I will give you that thing. If you give me a parameter of type something, then I'll give you a result of some other type. And by writing that function, you're proving that given one of these things, you can produce another thing, and that's a proof of an implication.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
With only like seven laws, you can construct a... all of mathematical logic in a type system. And one of the important things for programming languages that hasn't been given enough attention is some aspects of programming languages are just subjective. They're just machinations of the programming language designer. Guido van Rossum decided that Python should support indentation a certain way.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, as long as you're dealing with things like human notation and naming of things, there's always going to be that subjective layer. But there are other parts of programming languages that are not subjective but should be fundamental. And when you look at type systems, there is a way to do type systems that gives you mathematical proofs.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And every other way of type systems that doesn't give you mathematical proofs is just worse and should ultimately be rejected. Like, what have we actually done right in the past and what have we done wrong? And for everything we've done wrong, actually going back and fixing it. Otherwise, we just keep accumulating so much cruft that our systems eventually are crushed under their own complexity.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, there have been massive announcements of horrible vulnerabilities in software and services over the past year. It turns out, like, some nation-state backdoored a bunch of Teleco's surveillance systems for wiretaps. Like, huge problem there. But, you know, ultimately when you break it down, it's probably because of some buffer overrun and some C program.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
These decisions about programming languages have long-term implications.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Our worry is increasingly going away as society is ever more protective and sheltering and makes it harder to get these experiences.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
This is the one biggest technical problem that we're working to solve in this generation. And that is... taming concurrency so that any ordinary programmer can achieve it by just writing ordinary code. It's hard. Programming on a single-threaded computer is hard enough, but it is completely predictable.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you have a language that's deterministic and you run the same code over and over, it's always going to do exactly the same thing, and there's no unpredictability about what might happen. You're reading and writing variables in some order, and you're always going to see it behave the same.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The problem is when you introduce multiple threads or multiple nodes in a data center all working together on a single problem, is that they each want to read and write different pieces of data and change the state of the world as they go. And still, almost all concurrency in real-world programs today is achieved manually.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Programmers are writing this code that might run in multiple threads very, very carefully so that they are negotiating among each thread to get access to data in a way that's going to give them predictable results. And it's incredibly hard. It's so hard that we've...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
In five generations of Unreal Engine, every single generation decided we're not going to try to scale up all of our gameplay code to multiple threads manually. It's just much, much, much too likely to go wrong, not only for ourselves, but for every partner company who licenses Unreal Engine and tries to use it for building a game. It's just a massive foot gun.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I've had a funny relationship with games because my real aspiration was has always been to program cool stuff. I get more enjoyment out of programming than anything else in the world. And so my first really too formative experience with games were playing this game called Adventure for the Atari 2600.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's a variety of solutions to concurrency that are all rather suboptimal. One attempted solution was like, just don't try to solve this problem at all. Let's break our program down into microservices. And almost all online websites of massive scale, like amazons.com, work with hundreds of microservices where different servers negotiate with each other by sending messages to each other.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And by programmers writing those things very carefully, they eventually get to being able to take your orders and not make a mess of them reliably. But this is totally not scalable to the metaverse where you have millions of programmers who are mostly not going to be computer scientists. They're mostly going to be hobbyists and enthusiasts and first-time programmers doing stuff for fun.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's never going to work for them because they'll never be able to envision all the different dependencies between different computations that are running in parallel. But it turns out that there was an amazing foundational work done in the 1980s that was made very real by a paper on Haskell concurrency. Composable Memory Transactions is the name of the paper.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And it described the system for transactional updates to programs. And the idea of a transaction is... A transaction is a block of code that does a bunch of operations on memory. It might read, it might write, it might process an order, it might accept an order or reject an order. It might transfer money between one bank account and another.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It might make conditional decisions like, oh, you asked to transfer $100 from your account to this guy's account. We're going to see if you have $100. If you don't, we're going to reject it. If you have $100, we're going to take $100 out of your account and add it to this other guy's account.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Without transactions, if everybody's just randomly adding and subtracting each other's bank balances, then you might have somebody read a bank balance, subtract 100, and write it out. But in the meantime, somebody has written something else in the meantime. And so you might get inconsistent bank balances arising if you don't have a way of ensuring that these all run in a specific order.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So the idea of transactions is it's a way of dividing an entire program into updates individually. self-contained updates that do an arbitrary amount of computation but must run in a single-threaded manner. And in the case of a game engine, that's a gameplay object update. When you're playing Fortnite, you see a gameplay object. Every other player is a gameplay object.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Every enemy is a gameplay object. Every rocket and projectile and car and thing you see moving around and interacting, it's not just a fixed static part of the world. That's a separate game object. And each of those objects is updated at a rate of one update per frame at 60 frames per second.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so then in the course of Fortnite Battle Royale gameplay, you have tens of thousands of object updates happening every frame with 100 players. In a simulation with billions of players, you'd have a whole lot more than that. So right now that's done single-threaded. Yeah, that's done single-threadedly in each game session. This is why Fortnite is 100 players limitation.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you absolutely maxed out a server, maybe today you could get it up to 140 or something. But, you know, it's not going to thousands or millions or billions. And so what we need is a technique for magically automatically scaling our code. And transactions are the idea. And the idea is a transaction is a granule of code that runs its entirety.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so the idea of this transactional memory concept is that we're going to have programmers write completely ordinary code that reads and writes variables in the completely ordinary way, and they're not going to have to worry about concurrency at all. And then the system, like today, a computer just runs your program. There's no amount of speculation going on at the programming language level.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The idea of transactions is, since we have a bunch of operations we need to know we apply, we apply a large set of them concurrently, but instead of each one reading and writing from global memory shared by all, in which case they might be reading and writing and contending with each other for the same data and might be doing contradictory things to it, we're going to
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It was like, you move this dot around the screen and picked up objects like swords and fought dragons and invaded castles and solved puzzles. Very, very simple, iconic stuff, rather than realistic graphics. And then the other game that really got immersed in was Zork, which was a text adventure game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
track all of our writes locally. We're not going to write changes out to global memory. We're going to keep track of it in a buffer that's just for that one transaction.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So it's going to look to that code exactly as if it's running on the global system affecting global game state, but it's going to be isolated to just that one transaction, and it's going to be set aside and buffered up for consideration later. We're going to run tens or hundreds or thousands of these updates concurrently. We're going to see which ones had read-write conflicts.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Because if two transactions don't read and write any of the same data, then you could have run them in either order or simultaneously, and it wouldn't have changed the end result. Yeah, the order doesn't matter. This is so fascinating.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, exactly. And the key is that you're running these updates speculatively, and you're not committing their changes to memory until you're sure that they're free of conflicts. So you might update 10,000 objects. You might find 9,000 of them were conflict-free. So you apply those 9,000 updates to memory. And they could have run in any order, and it wouldn't have changed the result.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Now there's a thousand objects left over. Now you have to run those again, try them, maybe interleave in a different way to get them to eventually commit to memory. And in the meantime, you just throw all their computations away and redo them later.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And by doing this, like removing this from being a programming problem for the programmer to deal with to being a language problem for us language designers to deal with. And we're moving a vast amount of pain that would be imposed on a million people instead to a vast amount of pain in small...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, there's a lot going on in parallel. The key thing with Verse is that we have been specifying what we think is the ultimate version of the language with all the features we want, whereas we've been chipping more modest versions of the language over time. And we've released dozens of updates to it over the past year and a half.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the idea is that the shipping version gains more and more features over time, but each maintaining backwards compatibility with old versions and each continuing to improve and approach the ultimate version of it as we go. And we've been doing this experiment entirely within the world of Unreal Editor for Fortnite for now.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It would tell you where you are and what you see, and you'd type in commands like go north or pick up sword or open door and explore a world that way. So the game didn't have any graphics, but in your mind you had this elaborate picture of what you were seeing there, and it really brought in inspired imagination more than other things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We want to test this and iterate with Fortnite creators in just the metaverse usage case before we make it available to all of our partners using Unreal Engine for all of their projects. And the idea is to iteratively improve it and build it out. Because right now, UEFN has relatively few features for programming. It needs a lot more.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And everything we add makes the world a much better place for Fortnite creators. And we're adding major, major new APIs every few months throughout the course of this year. Whereas Unreal Engine licensees who are building standalone games already have access to the full engine through C++. They have massive, massive expectations of an API.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so we can't release this to them until we've built up all the essential features that they'll need for building their gameplay in the future. And so we have these two different tendrils of progress. There's Unreal Engine 5 for game developers, and there's Unreal Engine 5 targeting the Fortnite community.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And there's different bits of development that are only in one area of it that aren't applied to both. Not all of the Unreal Engine 5 features are actually available in Fortnite, because some of them we haven't figured out or haven't gotten to the point where we can deploy them to all seven platforms in a platform-independent way.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so the place where all of these different threads of development come together is Unreal Engine 6. And it's a few years away. We don't have an exact time frame. But we could be seeing preview versions of it perhaps two to three years from now. And we're making continuous progress towards it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The aim for UE6 is to bring the best of both worlds together. Much easier gameplay programming for the Fortnite community and for licensees. More scalability to large-scale simulations of all sorts. Greater ease of use, meaning it will be easier to hire programmers who are familiar with and experienced with the thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
but also ensure that every game developer has the full deployment capabilities so that it can build a game once and then ship it anywhere.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And playing those games led me to often want to learn to program everything I saw there. And that drove a lot of my programming. I learned how to move a player around the screen. I learned how to, you know, build a design tool so I could build castles and save them off and play them in a game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The ultimate version of this enables a game developer to build a game of any sort, either or simultaneously both ship it into Fortnite as a Fortnite island that players can go into, bring their Fortnite items and cosmetics and interoperate properly, or ship as a standalone game or both. And if they ship as a standalone game,
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They shouldn't be missing out on the open economy either, because in this time frame, we'll have opened up the Fortnite item economy to third-party developers of all sorts.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Hopefully they're a standards body, but there might be multiple phases of it, so that if you choose to ship a standalone game, you can still choose to have Fortnite items work in your game, and have your game items work in Fortnite, and have your item economy integrated with the overall metaverse economy, and make...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And solve the really core problem of the game industry that Matthew Ball has been documenting over the past few years.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, that's really about productivity. Because to be successful with a game, you have to have a great game. If you're building a type of game that nobody's ever built before, you might be able to build a smaller, simpler game than if you're competing in a massive genre that has huge expectations.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And I realized there was a separation between the tools that you use to build a game and the game itself, and that the more powerful tools you had, the more creativity you could unleash in yourself or others. And I learned all the programming techniques that supported games, how to parse text, pick up sword and go north.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But it's all about enabling somebody to do that in a reasonable amount of time that they can spend and to be able to finish it and chip it and maintain it successfully. The tools are a big part of that. Having the tools be as productive as possible. There are a lot of other facets as well. Having a content marketplace is a big thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Just off-the-shelf piles of content, some free, some paid, built by other creators, can enable a small indie team to... to build a big game and just be able to focus on the unique content of the game, being able to write their gameplay and lay out their environments the way they want, but not have to build every tree and rock.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Because somebody's already built one, and theirs is probably perfectly suitable for your game. And over time, there'll be more and more. There's also a lot of indie developers living as content creators. They'll be releasing content on Fab Marketplace or the Unity Asset Store and earn a living for that. But specialization of labor is a really, really valuable thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
In the early days, pretty much one person would build one game. That's how a lot of the games were built in the 1980s. Over time, you had a separation where artists became specialized and then programmers, and then gameplay programmers and engine programmers. Now you have technical artists, and you have dozens of different specialties contributing to AAA. 3D game now.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the more we can modularize those bits of content, so you could get something off the shelf rather than having to build it, or have the engine synthesize it for you, the more we can enable creators to create stuff fast and successfully.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Sure. Well, let's start from a very basic principle of computing. The first computer I owned was an Apple II Plus, designed by Steve Wozniak and marketed by Apple, and then an IBM PC. And in those days, anybody could write code. You're computer literally turned on with a programming language prompt in front of you.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You had to actually do work to not write a program and to instead run somebody else's program. That was incredibly empowering. And anybody could write a program. Anybody could put it on a floppy disk. Anybody could share it with their friends. Anybody could make copies of that, put it in a store. They could sell it. They could build a business around it. And they were completely...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
able to, without seeking any big tech corporation's permission, do whatever they want, even from IBM. Remember, IBM was the dominant computer company on Earth at the time that they released IBM PC as an open platform. And, you know, so it's really been firmly implanted in my mind that this was a magical and wonderful time of... unmatched economic progress for technology in the entire world.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
How do you make that sentence into an actual series of commands on the computer? And that was really, really exciting. I have to say, until the time that Fortnite came out, I played video games primarily to learn what they were doing so that I could go off and do it myself. I'd sit down when Wolfenstein came out and then Doom came out. I'd go through and look at it pixel by pixel.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Over time, the big companies have realized that they could shut down and just block software makers from releasing software on their own and block software makers from doing business with customers directly. And I've always viewed this practice as terribly abusive because when you buy a computer or a phone, you spend good money on it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's your money you spent on that phone and now you own that phone. And there's absolutely no reason that Apple should block you from installing apps directly from other developers directly, if you want, going to their webpage or writing your own apps without their permission and running them yourself without having to get a developer account, without having to go through their bureaucracy.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And there's no reason that any consumer who gets an app shouldn't be able to do business directly with the developer of the consumer. You already bought that phone. Why should Apple be adding a 30% junk fee to all commerce you do? And why do they selectively apply it to some things and not others?
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I've always viewed this as deeply abusive and that it shuts down the competitive engine that once fueled the app and software economy. It's still a vibrant competitive engine on Windows and on the internet, but it's no longer with mobile apps because these stores have popped up everywhere. And they don't provide any useful value to the user.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yes, they're a search function-defined software, but there's no reason other companies couldn't build a better one. And I bet if you had Steam, or if you had Valve build Steam for iPhone, I bet Steam for iPhone would be a much better app store than the iOS app store, and a lot of people would use it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that Apple would be forced to build a better app store in competition and that everybody would improve their products as a result. But, you know, Apple and Google shutting down the competitive engine that drives the software economy has massive implications for everything. And, you know, one of them is reshaping the nature of mobile apps to be really offensive to gamer sensibilities, right?
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you go on console, the best console games you see listed on the storefronts, the best console games that you see reviewed are awesome games that really have a lot of creative merit. The ones that sell the best are really enormous values for their money. and are the product of an immense amount of work. You don't see that on iPhone.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The top apps on iPhone, the top games on iPhone at almost all times are these ridiculously greedy, high-monetizing whale games, which are pervaded with pay-to-win and loot box practices. They have sort of a legalized form of gambling. And these games are not driven by fun. They're driven by manipulation of the players to greedy ends. Yeah.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And it's very hard for the fund-based games to actually succeed there. And the costs of operating these online games now are enormously high. So you have a game that's based on fun. It's not loot box heavy. You have to pay 30% of your revenue to Apple in order to just get access to the platform. And 30% is way, way, way more than most game companies make in profits right now.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so if that fee is more than the profit from a natural company, then they can only stay in business by raising prices. So these 30% fees are raising prices of all digital goods. It's just inflationary as a force in the economy. That's just the first direct tax. But then to reach users, when a user searches for
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Before Apple blocked Fortnite on iOS, when a user searched for Fortnite, the first result was always some competing game. That's utterly anti-user. You search for Steam for a game, and if that game's on Steam, it's the first result, always, because Steam's not getting inshittified with advertising. Apple is. And, you know, they do that so they can make even more than 30%.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I'd move the mouse very slightly and look at exactly what was happening to figure out what technique was being used there. That was puzzle solving at a grand scale, and it was so fun.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So if you want to be the first search result for your game, you're probably paying more, like 45%. If you want to reach users on social media, you're paying another 20%. So literally something like 70% of the revenue for your game is just going into... junk fees to acquire users and get them in your game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the money that's left over is only enough to fund these, you know, games with rather abusive practices that do not look to normal gamers like games for the most part. Now, there are some exceptions. There are some great games on iOS, and there are some games with good practices. But, you know, the engine has been really corrupted in a way that competition would fix.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you unleashed lots of competing stores on iOS, then you'd have lots of awesome options, and you'd have much better deals and much better prices.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
All companies are terrified of Apple, um, because Apple can destroy their business. Um, Epic was in a unique position with Fortnite. First of all, having the biggest game in the world at the time we started the fight with Apple. And second of all, having a majority of our users playing on PC and console meant that if we lost access to iOS during a fight, then we would still be able to survive.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That said, I pick apart Spotify, Facebook, you name the top 10 mobile apps, I think none of them would be able to survive without Apple. Literally, their business would be destroyed if Apple blocked access to them. Apple is incredibly... clear with developers that they're willing to deprive all users of access to any app if they get in a fight.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And if you look at how they dealt with Epic, they were not just legally maneuvering with the intent of winning the court case against us, they were also sending a message to all developers in the world, we will destroy your business, or we will try our best if you fight us. And a very small number of vocal developers have been willing to speak up.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And Apple was actually refrained from crushing their businesses when they weren't violating any Apple policy's And that took a bit of discipline, which I think is also an amount of calculation by Apple that they couldn't survive being seen as the company killer. If you criticize us, we'll crush your company.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But the other thing that Apple has that they can and will readily deploy against every developer is soft power. When they take 30% and advertising is so expensive, soft power by Apple, like approving your updates faster, Or slowing down all of your updates by a couple of weeks can also have a dramatic effect on your ability to compete successfully.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
In Apple, it's a very long history of playing cat and mouse games with developers. It's like a developer isn't in Apple's good graces, so just slow down the updates. So they've been slowing down updates for several major tech companies, sometimes for weeks, sometimes for months, all going under the radar because everybody's afraid to challenge them publicly.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so Apple's wielding a soft power can change a company's economics for the worse enough to deter almost any public company. And, you know, Epic is in the fight because I firmly believe that something like the metaverse will only arise. It's something like a billion-plus user, you know, real-time 3D social ecosystem that grows to encompass...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
potentially all or most major games by all major developers tied together into an open economy where they all participate as peers and they all compete to give users the best deals and they grow and do business with their customers directly. That thing can only exist if the Apple and Google gatekeeping monopolies are lifted. And it's not just the 30% fees.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The 30% fees are economically ruinous, but they impose other levels of control. Apple prevents all web browsers on iOS from implementing web standards better than Apple does. So Apple has really limited data storage capabilities and 3D graphics capabilities on the iOS web APIs, the APIs you can access from web apps running within a web browser.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It was a funny project because I didn't start out to build a video game. I'd just moved from an Apple II. So my brother bought my family an Apple II right after I'd visited him in California. So I'd been programming on that for a few years, learned a lot of techniques, but there weren't many Apple II users around still by the time that cycle came to an end. So I'd just gotten an IBM PC of my own.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, that's to intentionally cripple those apps to ensure that they can't possibly compete with native apps. And by depriving web apps of those features, they prevent web apps from competing with native apps. Well, you know, Apple, if they treat the metaverse the way they treat the web, they'll say you can only use Apple's metaverse engine. Unreal Engine is disallowed.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then they can impose all of their own limitations on the metaverse to force all commerce through Apple or force it to be... so uncompetitive and lousy that it can't compete. And they have this giant array of these anti-competitive techniques that they use to disadvantage other app developers, saying only Apple can build certain kinds of apps or only Apple can integrate certain features.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
In Europe, even where the DMA law requires Apple to allow competing stores, they say, a store can only be a store. You can't build a store into Facebook. You can't build a social network into a store. A store must only be a store because a store that's more than a store might be able to compete with us more effectively.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's just a giant, to use the Soviet term, it's a defense in depth strategy where they've constructed a massive series of barriers. each are fatal to any attempt to compete, so that even if one barrier is overcome, the others remain in place and shut down the whole scheme.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that's playing out in Europe, where Apple has enabled us to launch the Epic Games Store, but has made it so difficult and uncompetitive, both for Epic and for clients who we want to do business with, that it has no chance of success until the European Union starts to really enforce the DMA law and impose harsh and serious penalties on Apple to force compliance.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Thanks. Competition makes everybody better. You have a monopoly that's forced to compete. Suddenly the monopoly's products get much better. The offerings to consumers get much better. You see so many areas where Apple could be the best, but what they have is just really, really lousy.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And it's this old guard of leadership who is clinging to these old policies, turning themselves into the enemy of every developer, every regulator. And I think it's ultimately massively to their detriment. And I can't wait for a new generation to come in and paint a bright path to the future.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Epic was an awesome partner to Apple for more than a decade of demos and partnership and technology usage together. And we did amazing things together. I'd love nothing more than to have that Apple partnership. Bringing back Steve Wozniak's original views, the Apple II was such an amazing thing. It's a completely open platform.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The manual to the Apple II included a listing for all the ROMs, the source code to the ROMs, so you could understand exactly what was happening there and you could learn from it. It included a hardware schematic of the entire computer, so you could learn how to make a peripheral and plug it in in an open ecosystem. And that's the awesome Apple.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I was learning to program, and I realized I needed a text editor. So I started writing a text editor, A text editor is a program to edit text files. You have logic to move the cursor around and let people type things and backspace and delete and do all those mundane actions. One night, I had finished it up, and I was like, well, okay, I have a text editor, but this is pretty boring.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That company would be the best company in the world again. I think the current one It's just on the wrong side of history and needs to change.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Sure, yeah. I think one of the reasons that people characterize the Epic Games launcher as clunky is because the Epic Games launcher is clunky. And we need to improve this. There's a lot of work going on there, and I wish we'd gotten better at addressing quality of life features and prioritize them above all of the other features.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Because Steam has 15 years of built up work by many of the best programmers in the whole industry working on that. A much larger team working on Steam and a lot more time working on it. And so we've had to make a lot of prioritization decisions about what do we support with the Epic Games Store and when.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So I made the cursor into a smiley face character, and I had the different characters you could place in this document perform different gameplay actions. Some would be walls, and some would kill you, and some would be moving objects that could fly around the screen. And so this text editor I made evolved into a little game editor, so I was building these levels for a game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
A lot of the time, it's been supporting commercial features like merchandising, offering multiple versions of a game for sale, and offering upgrades from the regular edition to the deluxe edition and other things that partners work. And other priorities have been quality of life and launcher load times and other things. And we've not put enough emphasis on the quality of life features.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We've recognized this very clearly multiple times, and we've gone through multiple refactorings. But that's definitely been a disappointment to us and to a lot of users. And I think one thing it took us a while to realize was it's non-uniform. Depending on your proximity to a CDN and the size of your game collection, it can be either awesome or really clunky.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the users for whom it's really clunky are the people like... I think they're a large part of the complaints.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, and, you know, one of the criticisms of Epic Games Store from the beginning was you don't have all of the features of Steam. But we very much don't want to have all of the features of Steam. Like, Steam has forums dedicated to your game. And, like, we decide we don't want to create forums.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And our partners, when we talked to them, generally didn't want us to create Epic Games Store forums for their games because there's already... you know, channels that they prefer to them. There's social media and a number of platforms, and there's Reddit, and there's lots of places for gamers to discuss their game, and they prefer those discussions to be there.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so it's very much not our goal to mimic everything in Steam, but we do want to have all of the convenience features that makes it as easy and fun to use as Steam. So there's a long journey ahead. But we continue to reinvest in it, and we're working to build a multi-billion dollar business there and think we'll succeed.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Artie at the Epic Games Store supports an immense amount of Epic Games commerce and Fortnite on PC, now on Android and iOS in the European Union too. So it's a forever facet of the industry, and we are never losing heart in it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
At some point, I really feel that the benefits of the Epic Games approach are going to outweigh the benefits of the Steam approach, especially as gaming becomes multi-platform. One of the things that really sucks for all gamers is that You have a lot of friends in the real world. Everyone has different platforms.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Your Steam friends aren't connected to your Xbox friends, and they're not connected to your PlayStation friends or your Nintendo friends. And so you're very much bottling up PC gaming into a hardcore group of PC-only folks and making all the other aspects of it difficult. A lot of games have flocked towards Discord, which...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
is a mess in itself, because now your Steam name is not your Discord name, and that's not your PlayStation name, and so now you have two people in a game, and they have four different identities, and that sucks.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Our aim for that is, with Epic Online Services and the social systems that we built for Fortnite opened up to all developers to have cross-platform social features be super easy and free for all developers. This is not something we're trying to gatekeep or rent-seek on or lock people into. It's just a way that we're making social gaming easier for everybody.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
As more and more games follow the Fortnite approach of being multi-platform, especially multiplayer games, Metcalfe's always a very real phenomena in the industry. It's the thing that's upending some games and causing growth in other games. It is the number one trend for pervading the world of gaming today. And it says that, you know, your game is...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I put a lot of time into building an editor and a primitive set of objects, about 20 or 30 different objects, enough to build a really cool and compelling game, but not so many that players would lose track of what they're seeing. I started off just building different game levels. The idea is you'd be on a series of boards.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Quadratically more valuable the more percentage of a user's real-world friends they can connect to. Your game vastly benefits by connecting all of its players together and not segregating them off into different online platform populations and so on. And so I think the future trend is in that direction. I wish Valve had opened up Steamworks to just work on all platforms.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They could have easily done it. We did it. But they seem to be using it as a lever to keep people locked into the Steam PC game store. That's going to be a long-running battle, because there's always a very toxic group of Steam users. They even created an entire subreddit dedicated to criticizing Epic on our store.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And they create basically harassment campaigns at times against developers who use Epic Online Services. Developers do that so they can connect their players across platforms and have friends across platforms and voices across platforms. But suddenly that's trying to be turned into a negative effect.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They'd be connected by going north past the end of the current board would take you to a new one if it was open, or maybe it was blocked and you couldn't go there. I built this whole game world around that, and this was the game that became ZZT. And I was having fun with it, building it and playing it, but I didn't know if it would really work. So I did this experiment.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Thanks. Yeah, that was an interesting time. Sony had a long-running policy preventing cross-platform play. And we had a long series of conversations, which got pretty harsh towards the end. But Sony ultimately came around, and they opened up PlayStation. And through a series of private conversations, they did the right thing. Not only that, our partnership with Sony has increased exponentially.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
you know, since that argument back in 2018. And we've gotten closer and closer and done ever more things with, you know, Sony, you know, brand IP, like the characters in God of War and other games coming into Fortnite. And, you know, all kinds of crossovers, massive Unreal Engine adoption and Sony for making games, for making movies at Sony Pictures, music partnerships with Sony Music.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's been an absolutely wonderful relationship. I think That stands as an awesome example of a company that, because of historic reasons, got stuck with a policy that no longer made sense for the future. And following a serious discussion with a close partner, righted it and did an awesome thing. And now Sony is much better off and Epic's better off. And all game developers are better off.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the whole console industry, I think, is a lot stronger now than it would have been if, you know, these silos had continued playing out. And despite the kind of potential concern that, like, maybe blocking platform play with Xbox gave Sony an advantage, you know, Sony has actually grown in market share relative to Xbox since that time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so you can't say that anything but goodness came of that time. And I think a better version of Apple would have received... the email I sent to senior Apple management and been like, huh, there's an issue here. We should have a discussion. We should reconsider this. We should listen. And, you know, they didn't. And that's why we're in the midst of a five-year battle with Apple.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And in, you know, the, hopefully, still the early days of a 15 plus year partnership with Sony.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Let's back up and talk about the principles at work here. Apple forcing other companies to use their payment service is a coercive decision by Apple.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If Apple convinced other developers to use their payment service by offering benefits or a better deal or funding or any other positive incentive, then that would be perfectly fine. One is... preventing competition, and the other is actual competition. Epic has never forced any developer into any sort of exclusivity relationship.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I started inviting neighbors over, like some adults, some kids of all different ages, and sat them down from it and said, like, here's a game I made. Figure it out. And, you know, I had to force myself not to tell them what they need to do, right? Because I really wanted to learn if they were able to. you know, discover it all for themselves.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Rather, we've offered developers payment or incentives or marketing or any number of things of value to them in exchange for coming to our store exclusively. And it's their game. So it's entirely... rightfully up to them to decide how to distribute it and to make decisions about their business. It's their game. If they want to distribute it through Steam, they can.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If they want to distribute it through Epic exclusively, they can. If they want to distribute it through both, then they could do that as well. And if we pay them money or other things of value in exchange for them coming exclusively to the Epic Games Store, I think that's their right. And this isn't an example of Epic...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
an underdog with a tiny fraction of Steam's market share working to proactively compete with Steam by offering a better supply of games. And some consumers who prefer Steam might prefer that the game be on Steam, but the developer in each case has decided that they believe they would benefit more by doing this exclusive deal in exchange for benefits than by being on Steam. And, you know, like...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
One of the key exhibits in the Epic Google trial was its opening exhibit, which was trying to point out to the jury in the trial the benefits of exclusives. Like, imagine a new store popping up. The store has a big sign outside of it. We're the new store. We have everything that the other store has, and it's at the same price. Are you going to go to the new store? No.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Nobody's going to switch from Steam if Steam has all the same games as the competing store and everything's priced just the same. And so we looked at initially two ways of competing with Steam strongly. We wanted to sell games at a better price than Steam.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
By agreeing on the amount of money we pay each game developer, if the game's going to sell for $50 and we take 12%, we'd actually lower the price and potentially even lose some money to offer a better deal. We tried to pursue this, but very quickly, every developer told us that they wouldn't agree to better pricing because...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If they did, then Steam would stop giving them marketing featuring and benefits, and the console makers would be mad, and all their relationships would be harmed. So there's an undercurrent of powerful platforms and ecosystems encouraging developers not to compete on price. So not being able to compete on price, we decided to compete on supply by doing exclusive deals.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And we signed a lot of them, paid developers lots and lots of money. I think we distributed over a billion dollars in net expenditures to developers beyond the... the revenue we actually made from games in order to get a whole lot of exclusive games. Some were successful, some weren't.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Borderlands did awesomely on the Epic Games Store, and we and Gearbox felt that it did just as well through Epic as it would have done on Steam because the players who wanted Borderlands wanted Borderlands, and they came and got it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, today we would call this, you know, user experience test. And there's a whole field of research around user experience research. But back then it was just inviting some kids over to play the game. I took notes about what they got stuck on and what they enjoyed and where they felt bored and just iteratively polished the game until I felt it was good.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Whereas a lot of other games, some smaller games especially, that didn't have a dedicated audience that was absolutely going to play the game, typically benefited from exposure on Steam. They were reaching an audience they wouldn't have reached organically.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so some of them, in the end, we and they concluded that they did worse by being on the Epic Games Tour exclusively in terms of reaching fewer customers. And so we had these limited-time exclusives. When they ran out, they put their games on Steam, and lots of data was gathered to understand what worked. And so this worked well for some games, didn't work for other games.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But, you know, companies seeking to compete, especially underdogs seeking to compete, have to offer some unique value, have to offer something that's not available through the competitors. And I get that Steam users who just prefer using Steam and buying games on Steam or have the library in one place don't like this, but...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You're never going to have competition for better deals if you don't support the competitive mechanisms that allow competitors to come about.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think if Valve were forced, through Epic Games Store's success, to compete with Epic Games Store, then developers would be getting a better deal, consumers would be getting a better deal, and these 30% fees would be driven down quite a lot towards the actual costs that are required to support the stores.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And I put it out and released it on, well, this was before the internet. So there were bulletin boards. I uploaded it to a bunch of local bulletin boards. And from there it started spreading because, you know, the way to build up cred for bulletin board users was to upload new files and to claim that, Hey, I was the first that brought this to you.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, here's the conundrum. The exercise of soft power by all of the competing stores... has made it intractable for almost any developer to offer a better price through the Epic Games Store than through Steam.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You can imagine that if the effect of Epic revenue sharing 12% to developers was that games just cost 22% less on Epic Games, sorry, 18% less on Epic Games Store, that that would actually start to reshape consumer behavior significantly. People would start coming here for the better deals.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But I feel like Steam giving developers nasty phone calls and so on when they propose to do that prevents developers from passing on savings to consumers. then what's the mechanism that drives users away from the incumbent store to the store that offers a better deal?
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If basically developers are fearful of competing on price through stores, what can possibly be done to get a dominant store with something like 90% of revenue share among multi-publisher stores competing? you know, in line so that a much, much smaller store can compete? I think some answer is required there. A better UI is great. Like, Steam is super polished.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Epic Games Store and, you know, Time will hopefully be as polished. You know, how does that overcome the fact that your entire library over the past 15 years is there? If developers have been afraid to exercise their own economic interest, because it's in a developer's interest to sell on Epic and get, you know, 18% more of the revenue. I think there's a real power to incumbents.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's very hard to overcome through just being there and being as good.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, uh, you know, so there was a natural tendency of the software to spread. I decided to use the shareholder model, you know, so I didn't just build this one game. I built a trilogy of three games. Um, I released the first one for free and I said, Hey, if you'd like this, buy the two sequels. Um, and I, I included my parents mailing address and, uh,
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Thanks. One more bit on that exclusivity point is that when we told Google that we were going to launch Fortnite outside of Google Play and go into competition with them, they viewed exclusivity as such a powerful competitive force that they went around to the top 30 publishers and paid out hundreds of millions of dollars to them in order to agree not to do exclusive deals with competitors.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that was called Project Hug. H-U-G. Hold developers close. And that was one of the major pieces of evidence on which the jury found their practices to be illegal and anti-competitive. And the one more data point on that, you know, we talk about 30%, and there's always a lot of people defending Steam. Well, of course, they have more costs because they have more features than Epic.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We have data on that that's very detailed. The all-in cost of operating the Google Play Store, stocking it, maintaining it, the software, the entire ecosystem, is around 6% of revenue. So, you know, in a competitive market, would a company whose cost is 6% be able to charge 30%? Like, absolutely not. And Apple's costs are similar. Apple runs an even more efficient and lean operation than Google.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So their costs are also likely in the range of 6% all in. They market up from 6% to 30%. Like, only a monopoly can do that. Look at competitive businesses. They have a margin of a few percentage. The numbers there are strikingly supportive of just outright anti-competitive market distortions.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, there's one constant in gaming that I think the industry manages to lose sight of from time to time, astonishingly, and that's fun. People play games for fun. Our whole job is to deliver fun. When you look at a lot of the games that failed recently... they just didn't deliver fun.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Or they didn't deliver fun in a manner that was nearly competitive with the other sources of fun that exist in people's lives. And so, you know, at a basic level, we don't need a terribly complicated theory to explain a lot of the malaise in the game industry. There's been a degradation of the capabilities of a lot of publishers. partly because of competition for talent.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Companies with really vibrant game businesses like Epic or Riot or others are hiring the best developers and accumulating them. Big tech companies are hiring the best game developers because there's super talent there. In some cases, companies aren't competing robustly or getting worse. They're making games that are less fun and I think everything else that's happened is a sideshow to that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
He said, you know, send us $30 and you can get the sequel to this game. And the check started coming in within a few days. I was making like, getting three or four orders a day. I was making like $100 a day. I'm like, woo, I'm rich. Because, you know, being a 20-year-old, that was like a pretty big deal.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's always political drama and so on, but I think the core is a failure to deliver fun. The nature of fun is changing. It turns out that playing a game together with your friends in a really socially engaging way with voice chat is just way more fun than playing a solitary game for the most part. And there are exceptions to that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But I think we're seeing much, much more playtime shifting towards games you're playing together with your friends. And not just random internet strangers who happen to play that game too, but people actually know in the real world. And that's certainly been the case with me and with almost everybody I know who's playing Fortnite or similar games.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that has really significant effects in reshaping the whole game business. Because a single-player game, if you have 20 people with 20 different opinions of which game to play, each one might buy a different single-player game. But in a multiplayer game...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If there are 20 games out and each one might have their own completely individual preference and each one we're independently choosing which game to play, each one might buy a different game. But they're all realizing that they want to play together. And so what players are doing increasingly is playing...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
a game they like and accept together with their friends, even if it's not the game that every one of them might be preferring to play themselves. That's certainly the case in different Fortnite groups I play with from time to time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's like one player might have been preferring to play COD, one might have been preferring League of Legends, somebody else something completely random, but it's just so fun to play together, we're doing that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that means that there's really strong Metcalfe's law effect, in which games which are able to attract a large percentage of your friends are more able to attract you, and not only attract, but also retain.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so, you know, I think Matthew Ball's analysis of this over the years has really documented the trend towards, you know, you can call it the metaverse, or you can call it large-scale multiplayer social gaming.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
He's really documented this trend, and over the past year or so, it's taken a really, really strong turn towards increasing rate of change, increasing numbers of players coming to Fortnite. We hit an all-time high of 110 million monthly active users about a year ago.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And another close to peak this time. Roblox is bigger than ever, and this trend is players consolidating into multiplayer experiences as they play together. And we're seeing another trend overlaid with that, which is like when an awesome single-player game comes out or a small and multi-player game comes out, people often will treat it as a vacation.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They'll go off and play that game for a while, then come back. And I think Wukong was an awesome example of that. A wonderful game from a brilliant team. In China, they made a game that's like... Western players had really seen that type of thing done before, and it was awesome, and it did well. But most players played it for a while and moved back on.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that can be lucrative, but a business that's building that kind of game is going to have to build a new one every few years and build a business around that while the other games continue to accrete users. But when you have a large number of gamers migrating to a small number of games, the effect of that is great. Increasing revenue for those games, increasing reinvestment.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And there are things that Epic can do with a team of thousands of people building Fortnite. internally, and tens of thousands contributing to Fortnite as independent creators, there are just things that can happen with that level of investment that can't happen in a smaller game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so there's somewhat of an increasing winner-take-all dynamic where the biggest games reinvest more to make their games more fun. They gain fun at a faster rate than other games, and the industry is changing around that. I think the lesson for the game industry now is that there are really two big opportunities being pursued.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's big games or games that have the potential to be really big multiplayer experiences that keep players around indefinitely for very long periods of time. And then there are just really good single-player and small-scale games that people are taking a break from their big games for. And the trend there is going to be towards efficiently developing those games.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I looked at money always just as a tool to help you fund accomplishing cool things. And having enough to do the things you want to do is the critical thing. It's always been just very utilitarian. But the knowledge that other people all around the country and then a month later all around the world were playing the game, that was mind-boggling.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You can't build one of those games with a $300 million budget, but if you can do it with a $40 million budget, you can make a lot of money. So I think that's the main reshaping going on, and I think that... It creates a rather bleak outlook for a lot of the category of single-player games that don't have a huge audience to reach.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But this is just one of the trends of restructuring the business around the technology and changes of the day.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I'm most impressed with the games that have created what appears to be a full living, breathing world. Games that give you the sense that you're just a part of it and there's a lot more happening and there's always more. It gives you the sense that you can go anywhere and do anything. Even though these games really do have finite limitations and there are places you can't go, it really...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
creating that sense of wonder is just a magical thing like soda breath of the wild oh yeah yeah skyrim red dead redemption red dead is great yeah it's like there's an entire ecology simulator in there um i have a high school classmate that got into studying river ecology and he was commenting on like that like this this is one of the very few games that's hydrologically sound like yeah the way like they actually went to the effort of shaping the rivers to yeah
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
follow erosion dynamics and so on. It's the attention to detail. There's something there that's big. It's been funny journeying through the industry. I last designed a game in 1992. I'm not a game designer. I have a very open-minded view that the best game genre that will ever exist has not yet been invented. As we get more
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
technological capabilities and creatives, people use that and hopefully empowered by higher productivity tools and so on that we'll see more and more cool things emerge that we'd never dreamed possible. The idea of a world simulator is actually really interesting there. It's been tried a lot.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's usually extremely slow and expensive to create, but over time, maybe we'll get better at that, and that will be a thing too.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah. Civilization. It's mind-boggling. They build a game with that depth that can evolve so dependent on your actions.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That me, like this little kid who'd put out a game on a local bulletin board, could be doing international business and chipping discs all over the world to players because the software was spreading on its own. It was just magical. And that was a new thing for software. That did not happen with mechanical devices. You manufactured one, you sold it to somebody, and they had it, and that was it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's right. The best games have a soul. You can really sense it. Call of Duty has a very different soul than Fortnite, and it just kind of exudes not only in what you see in the game, but also in how players interact with it and interact with each other online. That's a really fascinating thing. I wish it would be studied more.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah. These old game design decisions that the designers make have a profound impact on what players think of the game and see in the game. Fortnite, Battle Royale, always had a sense of mystery to it. You're on this island, but you're not sure exactly what's happening here. There are all these houses. They're abandoned. Why? And, you know, I'm not the secret holder.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I'm, you know, I'm not on the design team. I experienced Fortnite as a player, but it really exudes a lot of that and a good spiritedness as well. Because even when you're eliminated in Fortnite, you know, there's not like
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
blood spurts and there's not good jobs you're just you know teleported out of the simulation and often you know you end up losing the game in a way that's hilarious enough that like actually you're laughing at it or you're like respect to that player who just won because that was clever um and you know it creates a very different dynamic than these other games where players tend to be very very positive towards each other um
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And one of the things I like to do in Fortnite, just to kind of gauge how the game is going, is I play fill squads, a match made with three other random players and play a game together. Sometimes they have voice chat, sometimes they don't.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And back when our matchmaking regions were bigger, I learned a little bit of Battlefield Spanish so I could speak with the people who are down as far south as Mexico City.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, the positivity of the interactions there among every kind of person you might ever meet online were really quite impressive and completely unlike what you would see in a game like Call of Duty where it's always, you know, everybody's got to be an edgelord.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But software could spread. That was just really cool to see, and it made me realize there's really no upward limit on the potential for a business like that. We saw Microsoft as the big juggernaut company at the time, but it was like, hey, if Epic does games good enough, we could accomplish what they've accomplished with operating systems. And the sky was the limit.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Making games is very hard, and especially when you're pushing the boundaries of something. With Grand Theft Auto, it's just the realism and feeling that you're in this huge city, and anything can happen, and it's all living and breathing, and you're just a part of it. The level with which Rockstar has brought quality to that genre is astonishing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And when you're building something at a level of quality and detail that's never been achieved before, you can't predict how long it will take. Whatever problems you're solving today, to get to the next iteration of quality on it, you don't know what new problems that will unlock.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And often, you fix one thing and make it super realistic, and that just highlights the unrealism of other things that you need to fix. I think the thing that always comes to mind is that shipping a game is easy if you don't have a high quality standard. You also won't have much success. What we've seen from Rockstar is they take a long time, but they ship amazing games.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And it's worth it in the end, right? A bad game is bad forever. A late good game eventually is released and is good forever.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We certainly do. We, uh... everybody's often working very much to the last minute to make something excellent. And it's really hard with these fast delivery timeframes because you really have to get a lot of stuff up and running before you can judge a new Fortnite season holistically. It's not until the last month or so that you really know what you've built and you really understand it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And if any late-breaking problems emerge in balance or anything else, it's usually towards the end. And that usually leads to a rapid push to... to fix it. And then other lessons you can only learn live from experience. And that means accepting a game that it's a live experience and it's also an experiment and it's going to continually be improving.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
At any time, there's some things that some people don't like and you learn from it and you improve it and you move on.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, I see two contrasting worlds that have been brought about in the digital age. One is the world of social networks and people typing at each other and just, you know, massive negativity and politics and, you know, hucksterism and, you know, Engagement, curation by engagement often promoting negativity and toxicity. That's a harsh world that I think is a step backwards in many ways.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And I think this is the age we live in now. You don't have to be an industrialist manufacturing physical products. Anybody who builds anything digitally, if it's good enough, you can reach the entire world and build anything. Next Microsoft or Meta or Apple or Google or Epic Games.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think the foundation of the world is actually a little bit shaky because of just the social dynamic that those platforms have brought on. But then I compare that with the good spiritedness of what's happening online when you're connected to real people.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Like actually playing Fortnite, playing Fortnite fill squads with people you've never met before, never talked to, and just judging what, you know, human connections develop there and whether they're positive. I found those to be really, really excellent and endearing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think the lesson from all of that is that humans talking to humans and being together in a simulated world, the real world or virtual world, is a naturally empathetic medium, which naturally leads to bonding. And though conflict sometimes occurs, it's just generally so much more promoting of our social norms and good
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
good interactions between people and positivity promoting, whereas kind of the typing angry messages thing at each other as a self-reinforcing negative dynamic that's negative. I think you look at social media and you look at gaming that is increasingly social, and I couldn't see a bigger divide between any two mediums as I see there in terms of the actual social dynamics.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
One super positive, one super toxic at times.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Oh, thank you very much. It's been fun.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, and a bunch of learnings emerged really quickly there. The neat thing I did with CZT was I didn't just release the game. I also released the editor with it. I built this tool so I could make these CZT boards that people could play, but I also gave it to all of the players themselves. And 30 years later, I still run into people. When I go to a game industry event, it was like,
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I grew up playing ZZT, and here's an adult who grew up playing my game. It was because it enabled anybody to become a creator, too. It had this little board editor, and it also had a little scripting language, so you could learn a little bit of programming in it, too.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It really set a formative principle of Epic, which was that the company's mission is to make awesome entertainment, but also awesome tools, and to share those tools with everybody so that they can build their own amazing things, too.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And when we got into Unreal Engine a few years later, the interplay between us building a game and us building tools that were widely used by others was a critical part of that. And I think that's the sole reason that Epic has been massively successful.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And actually, the reason that we've survived all of this time is that by serving both creators and gamers, we've been able to weather the ups and downs of the game industry. It's a brutal place for companies. And we've been able to survive every financial downturn. And sometimes the engine's been funding the business because we didn't have a game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And sometimes the games have been funding the business. And it really set a principle in our culture that's persevered and is continually brought to the forefront.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, and it's something we aim to do more and more fully over time. In the course of building Fortnite, we've built a lot of other tools that are useful for us too. It's not just a game powered by Unreal Engine, but it's also a social ecosystem where people can make friends and voice chat and get together and party. So we've opened up all of those social features into epic online services.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And we give them away to all developers for free because we all benefit from growth in that user base. Our goal is ultimately to build the company's products on the same technology that we share with everybody else and to help that foster a bigger and bigger ecosystem over time where everybody benefits.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So the internet is a funny thing. It started out as this defense department research project called the ARPANET, the Advanced Research Project Agency Network. And it was kind of like this revered secret thing that became more and more open as they connected universities. Universities connected to the internet in the mid-1980s. And so if you were...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
at a prestigious institution with access to computers, you could get on there. But the consumer back then, we just had these modems. This thing you plug into your phone line, and it dials up a phone number and then sends wild sound effects over the telephone line to send digital signals back and forth. And these were really slow. The first modem I had was 300 watts.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That means 30 characters per second. So you're like sitting there watching a sentence like slowly emerge character by character as you're going online. But yeah, that's how we got online and we talked with each other. So you dial up to a local bulletin board. It'll be run by a person. Usually they have a computer or two sitting in their kitchen or something that's running the bulletin board.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And they have a small community of a few hundred users all competing to connect to that one phone line online. It was often busy and you couldn't get in, and the more popular wooden boards were hardest to get to. But you had all kinds of communities develop, and you could see there was the programming communities where people talked about programming. There was the news and events community.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I lived in the outskirts of Washington, D.C., so that was a big thing. But then there was the pirate community where they were sharing pirated Apple II games, and very different community ethos and mantras out there, but all... You know, all really nice and also very small.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
These things, these wooden boards couldn't grow to the size of Facebook because your phone line couldn't take that many calls. And, you know, then later in the 1990s, the Internet, which had been fostered in these colleges, started opening up to the public and anybody could connect to it. And suddenly the world took on a life of its own.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It became much, much easier to reach a global audience faster.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, you know, it's been a funny transition for the game business. You know, Epic started out making shareware games distributed digitally. But, you know, as the first 3D games took off, like Wolfenstein and Doom from id Software, and then Unreal from us, took off, you know, to reach a huge audience of millions of users, we had to go into retail stores.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So we worked with a retail publisher, and they made a box, and they put CD-ROMs in the box, and... And then the world started transitioning back to digitally. And that transition didn't start well. The initial transition of gaming to digital was all bit torrent, all piracy.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And there are horror stories about games that would sell like 100,000 copies but have 2 million users because most people pirated it. And then Steam came along and introduced digital distribution and made digital distribution of legit games so convenient that most players moved away from piracy towards that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And their practices were then followed by others, and the early digital industry took form.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, you know, one of the critical things that Epic always worked hard to do was to make something different that nobody else was doing and to try to satisfy a small audience rather than competing globally with the game juggernauts.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, back in the 1990s, Epic was new, but Electronic Arts and Activision and the other big publishers had been around for a decade, and they were huge companies that had giant retail distribution networks If I tried to make a game and then convince them to publish it, I doubt I could have had a chance.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And I doubt that even if I made a successful game, that I would have made much money from it, though they might have. And so the really unique angle to Epic then was shareware. And that was just the idea that if we distribute our game differently, then we can reach a much larger audience than these bigger competitors by virtue of this first episode of the game being free.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It was kind of the advent of what later became free-to-play. And the logic of that is just as true now as it was then. If the thing is free and anybody can get into it, then it's going to spread from friend to friend as people bring their real-world friends into the games they're playing and have the opportunity to build up a community around that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So the other lesson there was minimize the friction of people getting into your game. Make it easy to get into and make it fun. I was very fortunate. ZZT was a funny game. It was not much like any other game. It had much worse graphics because it was all just text characters, smiley faces, and other Greek letters and things participating in this game simulation.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They were kind of iconic representations of characters rather than real ones. This was decades into the era. age of real graphical games with interesting graphics.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so it wasn't even trying to compete in that area, but it was able to compete in a different area, which is that it wasn't just the three games that I'd made and shipped as a trilogy that were successful and drove the success of the product. It was the fact that I released an editor, and there's a whole community around it. And you see that trend has repeated itself. There was...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
ZZT was one of it. Before that, there was Bill Budge's pinball construction set. That was a 1980s Apple game that let users build their own pinball tables. And since then, you've had some of the world's most successful games follow that path, like Minecraft. You can build your own stuff. Roblox. Fortnite Creative and Unreal Editor for Fortnite.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Games that become platforms for other people to build stuff was a real opportunity.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
you know i think the big thing to realize as for indie developers right now is like there's massive massive competition in every major genre and so it's very unlikely unless you just happen to be the world's best at a particular thing that you're going to release a game in an existing highly competitive genre and when um a much better chance of success uh is in releasing something that hasn't been done before being really unique and reaching an audience even if
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
big or medium size or small, reaching an audience and becoming really popular with that, making some money from it and being able to reinvest and then expand towards your ultimate dream.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think the one shot go from idea to commercial success at massive scale is a lot less likely than the multi-step process of continually build better and better stuff over time until you get into a position of excellence.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, that's right. Because if you look at every market, there's a few markets where the current leader came late to the space, usually because the prior leader failed so horribly. But most of the time, the company that's succeeding and winning in a market is the first or second entrant there. They've just continually buoyed their success.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I'd say it was the opposite of lonely because the thing that spurred me to actually release this was seeing kids playing the game in my neighborhood and having fun and being like, this is really good. And seeing them enjoying it and laughing and pointing at the screen and getting together and just wanting to play more. That's awesome.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the human element was always pervasive, because I did not only receive orders, but people would actually write letters. We wrote letters back then, in the 1990s. People would say how much they were enjoying the game and how their kids were playing the game and so on and so on. So we felt very connected.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, I think a lot of businesses have to make scary decisions because you're spending, you know, potentially all of the money you have to take a shot at something that you're not sure will succeed. I was very fortunate starting a business like this because it didn't really need any capital. The capital was, well, the several thousand dollars in computers I'd bought by mowing lawns.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And it wasn't much risk. If that hadn't succeeded, I guess I could have figured out how people get mechanical engineering jobs and pursued that. But once it took off and once the orders started coming in and people started writing letters saying they're enjoying the game, I knew I was going to go all out and try to build a company there and succeed. And that was going to be my big goal.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, that was a very interesting time. Epic had, after my first couple of games, had recruited developers, you know, usually college students, high school students who are just working on their own, had real skills, but didn't have an outlet for their work. Epic had been matchmaking the best artists and programmers together from all over the world.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Like Chaz Jackrabbit was Cliff Belusinski, a high school kid in California who'd made a really cool adventure game together with Ariane Brucey, a demo coder from Holland who'd make amazing graphical stuff and had built a 2D game engine. And it connected them together and a musician, Robert Allen in California.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And by telephone and modem and so on, we were building these little 2D games and having quite a lot of success. There were a bunch of people making thousands of dollars a month while they were still students in royalties from the games that Epic was producing by coordinating with people and publishing through shareware. And that was all going great.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The company had a little office, and we were copying floppy disks and mailing them out. But when Wolfenstein came out, we realized the future of gaming is going to be 3D. there had been a lot of experiments in 3D before that hadn't been great. There were 3D renderings of mazes that were not in real time, and you were always looking north, south, east, or west.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then there were vector graphics with little wireframes moving around and things, but... You know, Wolfenstein was the first game that was fast enough, you know, running at 30 frames per second. It really felt immersive. It felt like you were there, like you were in this castle of Wolfenstein fighting Nazis. And that was a really amazing and immersive experience.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
3D graphics were pretty primitive then. It software followed shockingly fast with Doom, which was a much, much more capable 3D engine, which had, you know, stairs and...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Though it was still what we call two-and-a-half-D, it was environments that were very realistic, textures that were very realistic, a form of lighting that was approximate but incredibly realistic, and just such great artistry and sound effects. It fueled completely visceral and real. You might look at it today from the point of view of a modern...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
a game player with 20 teraflops of computing power in your device and say, oh, that's not very impressive. But it was amazing at the time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You feel that you're there. Yeah. Especially when you turn the lights down in your room and you turn the sound up on your speakers and it will scare you. And you'll feel like, you know, that fireball that's coming at you is going to kill you. That was an amazing time because we hadn't experienced that before. There was nothing like that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, you'd watch a movie, a scary movie or whatever, you know, it was just, this thing that was happening. This was you. This was you in a 3D world.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, at first I was really depressed. Because the wizardry of Doom especially was so incredible that I gave up on programming for like six months. I was like, I don't know if I'll be able to compete with this. I have no idea what we're going to do. We just keep making 2D games and hope that the business goes on. But that was the nature of Carmack's wizardry. He had done things that were like...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
not just one innovation leap ahead, but like a dozen simultaneously, interplaying in a way that you couldn't pick them apart into their component pieces. But a funny thing happened. Michael Abrash, a long-timer in computer graphics, wrote a book on the techniques for 3D graphics and texture mapping.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And he wrote some articles in one of the programming magazines of the day and explained it and showed assembly code to do texture mapping, drawing these 3D graphics on the screen. And it was actually really simple stuff. I was like, oh, I can do that. And so a bunch of us at Epic independently went off and started writing our own 3D graphics code to figure it out.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And we found at one point we had a number of people dabbling in this, doing different parts of it. And at that point we decide, okay, this is 3D graphics. and 3D gaming is going to completely change the world. We need to go all in on this. And so we took the best people from our best 2D game development teams and put them all together to make a 3D game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We didn't really know what we were doing at the time. None of us had ever shipped a 3D game, and most of us were still learning, but everybody was trying different disciplines to see what they were best at, and It was a combination of a bunch of people who came together to make Unreal. I'd initially volunteered to make the 3D editor for the thing, and James Schmaltz had made Epic Pinball.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Epic Pinball. Now, that wasn't a crazy game. This was one of the 2D shareware games. He made it while he was in college, and he was making like $30,000 a month from the royalties from this game, because everybody had wanted an awesome pinball game. It was massively successful. But it was He was a multidisciplinary person.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
He wrote the code for the game, the art for the game, and did basically everything. And the code was 30,000 lines of assembly language. And so he was initially going to write the 3D engine, and I was going to write the editor, and he sent me his code so I could integrate it into the editor. It was like this giant pile of assembly code. I was like, hmm, why don't I just write this myself?
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so James instead started going off and building 3D models and 3D animations using the tools at the time. And so... And Cliff had done a lot of design work and built the levels on Jazz Jacket, went off and started learning basics of level design. And so I was writing this editor and Cliff Blizinski was customer number one for it, starting to go off and build levels.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And James Schmaltz was building awesome creatures, sending them to me, I'd get them implemented in game. And we brought in an animator to bring them into life. And we brought in More and more people until at the peak of Unreal 1 development, we had about 20 people working on it, which was a huge team for the time. It was really stretching Epic's finances nearly to the breaking point.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We barely survived and almost ran out of money a number of times, but somehow we always pulled through. It was a crazy project because it was three and a half years of development in a game that we always thought was six months from shipping. And... It was like three and a half years of 70 or 80 hour weeks for most everybody working on the project.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Not even knowing what problems we'd need to solve next because we were so immersed in the current ones.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We were always very financially stressed, so I was continually worried about that. I had total confidence that we'd work out all the technical and artistic problems, because we knew the pieces, and it was largely a matter of typing code in and solving some problems. We knew we could ship a version of it, and
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The thing that was continually really interesting was the ongoing discovery of new techniques as we went. Because at the time, Quake had shipped, it had a little bit of dynamic lighting. Unreal really pushed dynamic lighting much harder than anybody else had done before. Then colored dynamic lights with some shadow casting capabilities statically, or moving lights without shadows.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
figured out how to do volumetric fog, so you could have foggy areas that were full of lights, and you get the kind of glow of the lights standing out in the fog and affecting the appearance of the level. A whole lot of amazing techniques came together to build a game that made a number of leaps ahead of the state of the art at the time. Yeah, it was really crazy, but like...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think most companies wouldn't have survived that, but the sheer talent of the people involved made it possible. Epic has often done things that most companies would have failed at, and we succeed not because of awesome management or awesome planning or awesome financing, but because of the sheer talent and willpower of the people involved to make it happen.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, that's one of the really unique things that exist in gaming. Not in normal big tech companies, which are just engineering and business driven, but gaming really does require all the best people across all the creative disciplines working together. And Epic had grown organically by recruiting people with awesome talent. We always had a limited budget.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We could never bid up people's salaries and hire them away by paying them more. We just had to find awesome people who were at the beginning of their career and put them together. So everybody was very new to this and didn't have any assumptions about how companies worked. And so you put all these people together and
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It was really a constant interplay of talent as people were learning how to work together as a team. Nobody had management experience. Most people hadn't shipped a game before they worked with Epic. And we were figuring out as we went. But it was a constant iterative cycle. We'd make several new versions of the game every day.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Read a new compile, introduce a new feature, or fix some bugs, get it to the artist, the artist... improve their levels, continue building stuff, and then we see what they're doing in their levels, like, ah, I see what you need now. We'd constantly be improving the tools. And just the iterative process and the speed at which that improves products is the critical element to success in games.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The slower the iteration cycle, if you make a build every week and you go through one iteration every week, you're going to be way, way, way worse by the end of your project than a game company that makes new stuff every day. And that was the magic that happened together. And it wasn't, there was really nothing but passion and everybody's individual dedication to it that made it work.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, we'd all gravitated towards a schedule, a work schedule that maximized productivity. And that usually meant waking up late. I'd get to like, usually get to work around noon. Um, and we're usually work till like 2 AM or, or so, um, 3 AM sometimes. And, you know, I didn't have anything else going on in my life. So it was really just work and sleep and occasional eating. Um, and, uh,
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I found I always needed eight or nine hours of sleep a night. Without good sleep, I would just become a zombie and wouldn't be nearly at my best. So I always needed to get sleep. But I didn't need anything else going on. So the programming itself was so energizing and drawing. So it was three and a half years of that during the project. mostly spent programming.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Um, I'd say probably 60 hours a week of programming, five hours a week of coordinating with other people and iterating and, you know, sitting down with them and looking at what's going on in screen and figuring out what they needed. Maybe five hours of business stuff. Um, you know, there's a good division at labor, uh, labor then.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Um, I didn't have a big executive team, but it was like basically myself running the technical and development part of the company and Mark rain, uh, running the business part of it, doing deals and, uh, You know, maxing out his credit card and going around the world, bringing in sources of revenue to keep the company funded.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I'd grown up learning with Pascal as my favorite language. In order to just get maximum performance and get the latest operating system features, I had to move to C for my second game, Joel of the Jungle, a little Nintendo-style platformer. And so when I started Unreal Engine, it was on 16-bit Windows using the C programming language.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And over the course of the first year, it moved to 32-bit, using these DOS extenders and then using Windows NT, and I moved to the C++ language, and just because it simplified the code so much, went from a really complicated pile of code to a much simpler one, making that transition. And so almost the entirety of Unreal Engine development, about two and a half years of it, was all on C++, 32-bit.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Completely state-of-the-art then. Like, 32-bit protected mode was kind of a magical thing, having come from the days when computers were much less reliable and crashed all the time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, it's because it solves all the problems at scale, often through manual pain, but always solves them. A lot of other languages do better in a lot of theoretical aspects and are better for some usage cases, but you can't do everything, and that's very limiting.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I went through a big transition there. I started out being pretty lazy. I bought used computers because you'd often get them at half the price of a new one. They'd be good enough. I had this old 486 I was developing on. I guess it was a 15-inch monitor at the time. It was a poor workstation setup, but it was very economical. As we started on Unreal, I realized that I had to write a ton of code.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I had to write at absolute maximum productivity. So I had to rearrange my entire life around delivering maximum output. And so at that point, I realized actually spending money on getting good equipment was a good investment. And we're not talking about millions of dollars here or billions if you're building a GPU farm. We're just talking about buying some basic hardware.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so I bought the biggest CRT you could buy at the time because this was a CRT. It was 24 inches. It weighed like 100 pounds. I had back pain for a week after I installed it, but it got me 1920x1200 view in 1996. In 1996, that was pretty cool. So I upgraded to a 90 MHz Pentium and did a lot of programming on that. It was on the 90 MHz Pentium.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
These were the main consumer computers at the time, and I'd optimized the Unreal Engine software render on that, which was... And Pentium was the first superscalar architecture in consumer computing. It could run up to two instructions at a time. And if you wrote your assembly code very carefully, you could get absolute maximum throughput.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So I'd gotten my texture mapping code down to six CPU cycles comprising 11 instructions. And that was required for every pixel on the screen. And that was just enough performance to deliver that. But Dell came out with these new workstations, and Intel had just launched the Pentium Pro, the first out-of-order processor.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so I basically bought the absolute maximum configuration that money can buy. It cost $7,000. I had a gigabyte of memory in 1996. Wow. And a 200 megahertz CPU. So it tripled the speed of compiles and just made me massively more productive. So that's why I was using throughout Unreal Engine development and shipped with that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, at the time, so we did most Unreal Engine development before the first real GPUs came out. And, you know, the 3D effects Voodoo won. The first GPU that actually delivered serious performance compared to software rendering. The first GPU that was really gainful came out in the end of the development, and we supported it really quickly, but it was not the target all along.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so development was focused on just building... There are two parts of the engine, right? There's all the gameplay systems that manage the simulation and physics and so on. That's all written in very high-level C++ code. And maintainability is as much of a goal as performance, because we had to build massive amounts of systems over time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But the one thing that was really a bottleneck was graphics. the cost of rendering a single pixel was really high. And so you had to do everything you possibly could to optimize the rendering of pixels on screen. And so we were talking about how many CPU cycles. When you say your CPU runs at a gigahertz or whatever, that's a billion instructions per second.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
How many instructions do you need to run to get a pixel on screen? And so there's a constant challenge to optimize that down. And, you know, there was also a competition among all of the graphics programmers who'd often send emails, you know, like bragging to each other about what new technique they've discovered, you know, to try to get the cost down.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And Abrash's original articles took like 12 CPU cycles to render a pixel. And, Everybody else had figured out how to get it down to six or sometimes even four cycles. And that involved lots of different trade-offs of caching and memory hierarchy and so on.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It was just like a magical time where a human could actually understand exactly what the CPU was doing under the hood and could write code that exactly targeted that. And that's largely lost now. When we talk about optimization software now, it's largely about heuristics. And statistically, this memory access is likely to hit the cache. And this algorithm is faster than that algorithm.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Because CPUs now have such advanced out-of-order execution, you really can't micromanage what's happening on an instruction-by-instruction basis. You can only manage the aggregate performance of code. And so there's kind of this lost art. Some people miss it, some people don't, in which the programmer had absolute control over the machine and could work miracles in special cases if he tried.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, that's absolutely so. The optimization problems have just moved around. In a system like Nanite, the virtualized micropolygon geometry system that Brian Karras, a brilliant engineer with Epic built, was just one of those multi-year problems.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
optimization efforts that required him understanding everything from the highest levels to the lowest levels of the hardware to figure out how to make this breakthrough technique work in a way that was actually maximally performant on GPUs.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, you know, with the advanced art tools we have today, it's really easy to create a scene with billions of polygons. The hard part is how to render it efficiently because you can't render billions of polygons in a frame. Basically, you want to render an image that's indistinguishable from the full detailed geometry if you rendered it at ridiculous cost.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so the challenge is how to simplify every component of the rendering, the geometry, the lighting, and so on, down to real-time techniques. They're efficient. They capture a realistic view of what's around you. And so when an object is up close to you, you want to render it with a lot more polygons than when it's far away.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But one of the cool principles of mathematics is the Nyquist sampling theorem. It says if you're trying to reconstruct a signal, there's a limit to the amount of data you need to bother capturing. If you want to render a texture at a certain resolution, then you never need more than twice the pixels in the texture that you have on the screen. And that's called the Nyquist limit.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
One of the challenges of computer graphics is given the need to render objects at extreme close-up distances and extreme faraway distances. You always want to be able to generate the right amount of geometry so that you have enough to be indistinguishable from reality, but not any more than necessary.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And with geometry, the idea is that if you render two triangles per pixel, you should get an image that is indistinguishable from reality. thousands of triangles per pixel. If you render less than two triangles per pixel, you're going to start to see visible artifacts of the loss. And GPUs have this amazing hardware in a lot of different pipelines, but it's all very fixed function.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's pixel shader hardware, there's geometry processing hardware, and then there's triangle rasterization hardware. One of the limits of GPUs is that the triangle rasterizers are built for pretty large triangles. If you're building a triangle or rendering a triangle with 10 pixels, that's pretty efficient. But if you're building or rendering a triangle with one pixel, it's very inefficient.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So one of the breakthroughs Brian made was to design an entire pipeline for avoiding the rasterization hardware in the GPU and just going straight to pixels and calculating what should be done with that pixel as a result of some ray tracing and geometry intersection calculations done in a pixel shader.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So instead of using the triangle pipeline, we're just using pixel pipeline and getting a better result.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, yeah, that's right. But there's a lot of challenges like that. It turns out it's a lot easier to render one frame that looks perfect than it is to render a series of frames in motion that look perfect. A lot of the problems with the earlier algorithms that aspired to do this sort of thing was popping.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You'd be running some number of triangles for a while, and then you'd switch to a different number of triangles, and you'd see a visible transition, and the screen would look like it got shaken up. It's a disturbing artifact that distracts you from the game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so one of the magical trade-offs of Nanite was how to avoid all of the visible transitions and get them down to a point where, though they exist statistically, they're not really perceptible to a person looking at it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, Unreal Engine is a big bundle of code and tools, a huge software package that provides all the functions you need to build any sort of a 3D graphics application. Game developers use it to make games, and that's the predominant use, but it's also used in Hollywood film and television production to create 3D scenery in real time for production sets, to do pre-visualization.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's used by car makers to visualize their cars before they're
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
constructed or manufactured um it's used by architects to preview buildings before they're made and industrial designers of all sorts and it provides you know the all the 3d simulation features you need both for creating highly realistic 3d graphics but also physics and interactions between objects and making things happen like you might see in the real world um
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And it supports a huge variety of styles, from Pixar-stylized movies to cel-shading to photorealism. And it can be used for anything that needs real-time 3D graphics.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, well, the philosophy began with ZZT and continued onward. We're not just building a game for players to play. We're also building tools that could be used for building that game or any other game and catering to all the artists and designers who would use the tool. And so that philosophy started at the very early parts of Unreal development. I was building the tools for...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
level designers like Cliff Pozinski and artists like James Schmaltz. And as we began marketing the game, thinking it was six months away, we were constantly releasing screenshots and things like that, other companies started calling us and saying they wanted to build 3D games too, but they didn't have the expertise for that and they wanted to license our 3D engine.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And this was one of the coolest pivots in Epic's history. Microprose called up Mark Raine, our vice president and longtime business guy, and said they wanted to license our engine. And Mark Raine was like, oh. What? You want to license what? An engine? What engine? And they explained to him what they wanted to license. He said, oh, that engine. Yeah, yeah, that's very expensive.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But this was one of the critical things that kept Epic going through that three and a half years. We were starting to license our engine out to other developers. Microprose took two licenses, and we got in half a million dollars from that. And the company, GT Interactive, licensed our engine to build... another game, and we got paid for that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We had this revenue stream funding the development of Unreal Engine from other games that were being built by other developers. Because they were the lifeline for the company, we took the engine business very seriously from the start. We set up... mailing lists so that our partners could ask us questions.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And all the developers and artists working on our games were participating and helping customers. Everybody took that very seriously because it was our funding source. And that's kind of set this dual spirit of Epic of building technology and supporting game developers simultaneous with building games and supporting gamers. It's continued onward and just grown over time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's a lot. Some of them are visible on screen and some are behind the scenes and still require a lot of innovation. All the graphical techniques were really interesting challenges. An Unreal Engine in those early days went a lot further than the Quake Engine in building environments using constructive solid geometry with a real-time editor. That was a really interesting technical challenge.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The idea is Building is extremely tedious if you are only adding objects to the world. If you want to build a door, then you need to add a dozen different pieces of door frames and add a bunch of different walls together to fit together in the right shape. It sure would be easier if you could just start with a wall and subtract the door out.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so we had this way of adding geometry to the world and subtracting geometry, and the engine would perform all the calculations on that. And this is something that I'd been anticipating was possible for a long time, but when I finally got around to it, it took this 30-hour coding session to figure out all the special cases of the code that needed to be implemented to make that work.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
In the course of 30 hours, I got constructive solid geometry up and running. I started doing, like handed it to James Schmaltz the next time we were together. And it's like, okay, I think you're cheating here.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So you create a giant torus and then add another giant torus interlocked with it and then subtracted a cylinder from it and created this really advanced composite object with just three operations. He was like, whoa, I can't believe this. It's like, yeah, we figured it out. And that was cool to see for the first time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It was probably the first time somebody had done constructive solid geometry in real time. But it was also a really useful artist tool that all the artists appreciated and immediately began making use of.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
your brain works in different ways depending on your state, right? There are some things that require really working on a problem fresh, where you've put together a bunch of logical pieces and now you just need to write a whole lot of code to make it all work together and plumb a whole lot of data between a whole lot of different algorithms.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But I think our brains have vastly more horsepower than we're able to directly access by thinking of what code to type next. after you've been working for a very long time, you can get into a sleep deprived state where you have much, much more direct access to that low level knowledge. That's great. Yeah. You know, because there are symptoms that are well studied of sleep deprivation.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
One of them is, um, short term memory loss. And so you're working without like the easy recall of the code you just typed. Uh, but your brain is then freed to, to think about other problems. And, uh, And I built up this intuition over a very long period of time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So the foundation for the subject is the binary space partitioning tree, this data structure invaded by a computer science graphics researcher, Bruce Naylor. Carmack had picked up on that and had used the technique in Doom to really great effect. And I'd picked up on that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And no one really was using this technique for all of its graphics and rendering, but it was just additive geometry everywhere. And it had a lot of overlapping polygons and was pretty inefficient. So I had the idea that if we had a BSP tree, there was a really efficient way to do constructive solid geometry.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And to do that, you had to break down the ways that different pieces of geometry can fit together. I broke it down into like 14 different cases. And most of them are pretty simple. Crank them out. And as I got towards the end, there were some pretty complicated things. Like, how do you deal with... coplanar polygons.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They're in the same plane and pointing in the same direction versus the other direction. In what cases should you keep them? In what cases should you eliminate them? And so on and so on to create really efficient geometry output. And just plowing through it eventually through mostly deduction, but some trial and error too. Sometimes you just have to try the possibilities and see what works.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, I cranked it out and it worked. And the next day I came in like kind of weary and I was like, oh wow, this actually did work. It wasn't just a dream.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, you know, it's pretty easy to write software that's like 99% correct. It's the 1% that's the really hard part and where the devil lies in the details. What about lighting? Is there other interesting... Well, the funny answer is we know the laws of physics. So it's actually really easy to do everything in computer graphics. But the direct solution of the laws of physics is immensely slow.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so what we're finding are approximations rather than complete solutions. Because you need something that's a million times faster than the brute force answer.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, photon tracing is the subject matter that does brute force calculation of pixels on a screen from all of the light in the scene. And it works, and it's correct, and it just is an implementation of the laws of physics, and it's millions or billions of times slower than what we do.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But Carmack had figured out how to do really cool lighting algorithms, including real-time lighting with objects moving around. And I hadn't taken it very far, so... With Unreal Engine, I'd realized we don't have nearly enough computing performance on our CPU to compute the light of every pixel on the screen from all of the light sources that affect it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We're at a six-cycle texture mapper, and we couldn't afford 30 more cycles for lighting. And so the answer had to be some approximation. And the one that Carmack had picked up on in the Quake Engine was light mapping. Instead of calculating all the lighting on every pixel, what if we made a big texture that we placed over all of the walls in the scene that was like wallpaper.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And what if we say every foot, we're going to compute a lighting value for just that one foot grid on the object rather than computing it everywhere. And then if we, what if we just linear interpolate that? over the course of it. You know, you get a lighting solution that actually works pretty well and is fast enough to work.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so a lot of Unreal Engine's lighting techniques were based on light mapping. We introduced colored lighting. So you could have colored light sources. Then we realized, oh, since we're doing this and we're doing it on light maps, we can actually do some pretty expensive calculations, hundreds of cycles, since we're only calculating it for every one foot of world space rather than every pixel.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so we introduced a whole bunch of elaborate lighting effects, like torch flickering and the caustic effects of water bouncing off of a surface and so on, and pulsing lights and blinking lights and everything else, and I created a system for compositing them together. So if you had an arbitrary number of light sources, they could all do that. Then I implemented a shadowing algorithm.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you cast a ray from a light to a point on a surface and see whether it intersects any other geometry, if it doesn't intersect, then the light hits the object, and if it does intersect, then the light hits something else first, and that pixel on the object should be dark. So I built a real-time version of this, and it ran at about a half a frame a second.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So I was running around at half a frame a second, like shooting out light projectiles and looking at dynamic lighting. It was like, someday computers will be fast enough for this, but not today.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So I made a non-real-time version that pre-calculates all the lighting and realized, oh wait, if you pre-calculated the shadowing in an object, you can still apply the lighting dynamically as long as the light's not moving.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So you could do torch flickering with shadows and figure out all the cases of dynamic and static lighting that were actually practical on a computer at the time and expose them to artists and This was the wonderful thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I was just typing in these little features, exposing them to artists, and every day they'd find a dropdown with some more lighting options available to them, and they'd start using them, and they'd do things that I never thought possible. And this was always the coolest thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
As a programmer building an engine, you might think you know the implications of the feature you're building, but artists are so clever that you always find that you've built the capability of doing vastly more than you ever anticipated as they start to use combinations of features together in concert to do ever more amazing things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's right. And it's timeless. What do the Renaissance painters do with paints? And what do the early game artists do with early engines? Everybody's figuring out the capabilities of their medium, and you're seeing a revolution.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah. Well, it's a funny thing. So this graphics hardware company had just started up in Finland, and they released a screenshot of what their GPU was doing, and they showed a scene filled with volumetric fog. So you had a foggy room with some light sources in it. And when that happens in the real world, what you see are glows around the lights as the light brightens the fog around it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But the brightening of the fog diminishes over time because the fog absorbs some lighting. And so the further you get away from the light, the more the more fall off there is. And, you know, you have a bunch of colored lights overlapping together in a space like that. The effect is just absolutely magical. You know, like being out on a foggy light with street lamps above.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's something that's surreal and just beautiful. So it's like, oh my God, they figured out how to do real-time volumetric fog. I have to figure it out myself. And so that was another 30-hour coding session. Nice.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But at the core, I realized, OK, what's happening here is we have this lighting function saying that light at a particular point in space is falling off with the inverse square of the light, the distance from the light source. The inverse square is all from Isaac Newton, which applies to lighting.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I had to realize was that the way the fog interacted with the light was that you calculate the view from your eye's position to a point on a surface in the world. It's going through fog and you're accumulating more and more light as a function of the amount of light illuminating the fog at that point in time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so, well, you know, I'd studied that in mechanical engineering without even knowing it. That's the line integral. You know, you have an integral over a line of some function. Well, this is exactly what it's for. It's for accumulating values of a function over a continuous space and time. And
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, I did a bunch of math and realized that, oh wow, the integral, and then I looked in a reference book of all of the integrals, and thankfully people had solved them all, and I realized the integral of this transformed 1 over r squared turns out to be solved by the arctangent of r.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so, you know, if you calculate some parameters based on the position of the eye and the position of the surface point you're ultimately seeing, then you calculate exactly how much fog you can accumulate from that. Of course, you can't do that per pixel because that's hundreds of cycles of CPU time. And so what we had to do is calculate volumetric fog on...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
on something equivalent to a light map but uh calculating fog every square meter in the world um and so you know we had enough performance for that built uh volumetric lighting and gave it to the artists and they started building magically detailed levels with volumetric fog and in real time and then um you know decades later i was talking to one of the engineers who'd worked on that hardware and asked about their volumetric fog and told him how it inspired me to um uh
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
to figure out how to do it in real time myself. He was like, oh no, we cheated. We just rendered it out of 3D Studio Max. That's awesome.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I had a brother, Steve Sweeney, who was 16 years older than me. At some point when I was a little kid, he went off to work in California for a tech company, and he'd gotten one of the first IBM PCs. So for one summer, I think I was about 11, I went to visit him in California. It was my first trip away from my family, just to hang out with him.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
to getting the best result from his code and having absolutely no attachment to passcode. And some of the legendary things he did, the end result was an absolute breakthrough in real-time computer graphics, weren't his first try. They were like,
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
His seventh or eighth try after he'd done something time and time again, tried it, found a better approach, thrown out the old one, built it again, and continually rewrote his code until he found the absolute best solution to a problem. And I think that stands as a lesson for every programmer to pick up on.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
When something is really, really important, its performance is absolutely critical to the product, or its quality, or its capabilities, just Iterate on it until you've achieved perfection, and don't settle for the first or second solution is good enough.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's been an astonishing experience. Nobody 30 years ago had anticipated that we'd see the performance gains in hardware that we've actually seen in that timeframe. It's something like 100,000 times higher CPU performance between multiple cores and higher clock rates and more parallelism. If we had that in aviation, then we'd be taking a trip to neighboring stars. Alpha Centauri, yeah. Exactly.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And in graphics, it's been even more so. It's something like literally 10 million times more net usable GPU performance than we had back running on a Pentium 90 CPU, all in 30 years. And it's really made me appreciate that over the generations, some areas of our engine development have absolutely kept up with technology.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
He had this brand new IBM computer, and I learned to program over the course of a few days in BASIC. I was just blown away. with the capabilities of computers at the time. It was unbelievable what they could accomplish. And I was hooked from that point onward and very much wanted to be a programmer.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the rendering team that works on Unreal Engine are the real miracle workers there. Just about every generation of Unreal, we've replaced most of the rendering code. And the different leaders in different points in time and the different luminaries have built systems that were absolutely rethought and optimized for the latest generation of hardware.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Unreal Engine 1 was built for software rendering, and then the Voodoo 1 came along late in the cycle. And we had support for it, but it wasn't fully fully capable and utilized. Unreal Engine 2 was about bringing all the latest GPU hardware acceleration features to the Engine and keeping forward and building some new features like vehicles and a few other capabilities.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And this was in the early GPU era, before GPUs had really broken out of everybody's expectations of Moore's Law. But that breakout occurred with DirectX 9 and the capabilities of programmable shaders.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Once you had control of writing code running on the GPU that could color every pixel on the screen, and that GPU code was literally a factor of 100 times faster than the equivalent code I wrote a few years earlier on the Pentium 90. And so that DirectX 9 generation was a godsend.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And Andrew Scheiderker, a longtime Epic luminary, wrote the core of the Unreal Engine 3 render around real-time pixel shading, real-time lighting, being able to do dynamic shadows using several different techniques, and multi-thread the render to support bits of the early dual-core CPUs that were starting to show up at the time. And it was a massive, massive graphical upgrade.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Unreal Engine 4 made a number of improvements and just continued to add features to give artists more and more options for lighting and for geometry that created realism.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But then I think probably our biggest single level of leap came with Unreal Engine 5 with Nanite micropolygon geometry solution and with Lumen, the global illumination lighting solution, which I think really bridged the gap from game-ish computer graphics to... total observable photorealism for artists who wanted to create that. And so that's been the evolution.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the progress on the graphics side is absolutely astonishing, as it is on the audio side in a number of other areas. But parts of the engine also haven't changed all that much since the version I wrote and shipped in 1998. You know, the file management system has been optimized a number of times, but it hasn't been completely rethought.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the networking system, the ways that clients and servers talk together and negotiate game state is still an evolution of the thing I wrote. And, you know, it's feeling kind of dated now. You still see networking bugs in Fortnite where, for some reason, when you're spectating, you're not seeing some parameters update. Well, that's because of the lossful nature of that networking model.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the biggest limitation that's built up over time is the single-threaded nature of game simulation in Unreal Engine. We run a single-threaded simulation. If you have a 16-core CPU, we're using one core for game simulation and running the complicated game logic because single-thread programming is orders of magnitude easier than multi-thread programming.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And we didn't want to burden either ourselves or our partners or the community with the complications of multi-threading. And over time, that becomes an increasing limitation. So we're really thinking about and working on the next generation of technology and being Unreal Engine 6.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that's the generation where we're actually going to go and address a number of the really core limitations that have been with us over the history of Unreal Engine and and get those on a better foundation that the modern world deserves, given everything that's been learned in the field of computing in that timeframe.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, it's funny. I have a perfectly vivid memory of all of the first things I learned to program. I have a hard time remembering people's names, but code really sticks with me. Every step and every challenge, there were lessons learned. Some of which I've come to realize were just me getting over some learning hurdles, but other things were actually shortcomings of programming languages.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's a lot happening here on screen. The real hero of this image isn't Epic. It's the artists and technical artists who worked together to build this environment. The reason we showed it at GDC was it went way, way beyond what we realized the system was capable of doing, largely because of their brilliance. This is the magic of computer graphics. There's not one feature that makes this cool.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's a dozen technical features that each interplay. Because of the ways that they... interplay with each other. It's hard to actually identify the individual components of it. One thing that's happening here that's really critical, oh yeah, now we're seeing it being turned off, is the lighting happening.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The lumen lighting system that's powering the scene is doing different kinds of lighting calculations at different scales. This was the work of Daniel Wright following a decade of moving the state of the art of lighting forward. But his theory, which was rather controversial at the time, was that if you have enough levels of lighting calculation, then you can get everything...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the realization that there are actually better ways. And when a programmer is learning to program for the first time, a lot of what they're facing isn't the challenge of learning a new art. It's the friction introduced by failures of programming language design.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
global illumination working everywhere from the absolute highest levels of a scene, you know, that buildings are casting cracked shadows all the way down to details like you see on the dirt here, all working in concert and without distinguishable boundaries. So there is a good decade of foundational work there to make the lighting work. In particular, when you see that
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
very detailed shadows interplaying between the ice and the dirt there, that's screen space sliding. There's actually shadow calculation going on, not based on the world, but on the pixels on the screen, because that is the only way that we could possibly do those calculations fast enough, running them in a pixel shader. Yeah, watch this.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That shadowing is an amazing thing, but the reason that works is counterintuitive. When somebody first explained it to me, I was like, that's really clever, but I don't think that will work. But it does work, because if you observe the positions of incoming light and you know the Z coordinates of the different pixels on the screen, you can figure out how...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
your geometry there is likely to include other geometry. And even though it's only an approximation and isn't perfect, it looks perfectly good to the human eye and gives you the subtle shadowing that you see in a scene like this that makes it look highly realistic. And the shadowing influences other things There's also some really interesting things happening with the color here.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I'm not even sure what's causing it. It looks like color is bleeding from some parts of the snow onto other parts of the snow. It looks like there's some subsurface scattering going on. I'm not even sure if that's being used. in the scene. And then there's a material layering system for laying down layers of material, dirt and snow and other things, all making that work.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so I've constantly come back to those early lessons there as I've progressed and done more and more things, including building programming languages.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then there's the light bouncing off of the geometry, which is another system for lighting on top of the global illumination system.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, yeah, that's right. The engine supports a number of different reflection techniques. One is calculating basically textures that reflect, that capture all the lighting in the scene, and then bouncing that off of texture maps so you can see different lights bouncing off of different pixels in different ways. And then there's individual lighting casting reflections off of things too.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And a lot of this is under the control of designers. And one of the things that's yet to do a problem for the future is... You don't just press a few buttons and this kind of scene magically appears.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
This is a lot of work from some highly skilled people, not only building out this particular scene, but in setting up the material layers so that you get the dirt with the ice layered on top and all the reflections working. And they had to make a number of technical art decisions to make this work.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And if a novice who hadn't worked very hard built a kind of scene like this, it wouldn't look nearly as good. So one of the challenges we have is to make building this kind of quality level even easier and more seamless and automatic. You'd like to just build a scene and say, use this material here and have this appearance come out of it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
This is the power of awesome technical art, three decades of feature development, and you have to credit it also to the 20 teraflops of graphics performance that NVIDIA is delivering. Thanks, NVIDIA. 90 megahertz to this. 90 megahertz is 90 megaflops. This is 20 teraflops. That's a big change.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah. That's really cool. It's a cool system for material layering and a dozen pieces coming together here. You also notice there's fogginess and there's some hot objects emanating fog. An artist did that. That didn't just arise automatically.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, layer materials on top of each other and see how much of each material should be protruding in different places with the engine handling transitions and things like that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, that's all real time. What the hell? How do you do that? How do you do the smoke? Well, there's a really powerful particle system underneath. It's providing the technological foundations for this sort of thing. But there's awesome artistry on top of that. and an awesome physics engine powering it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's hard to tell exactly which piece is doing what, but you have several different particle systems there. There's one for the fire, and then there's another one for the smoke coming out of it. The really interesting thing happening with the smoke here is that it's occluding light.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's calculation of how the light should diminish as it travels through smoke, and so you're seeing the lighting on the smoke being the really interesting thing. And there have been a lot of attempts, but this was the first demo where I felt like this kind of smoke had really no longer looked like a video game. It looked like just a burning trash can, billowing out dark smoke.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, yeah, it's the artist's sophistication. It's a very, very, very large part of it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, in the early days, I wrote a little bit of everything. I wrote some games. The first game I wrote on the Apple II was, since I only knew how to program in text mode, the computer would throw asterisks across the screen. They'd flow from left to right, and you'd have a parenthesis on the right-hand side of the screen. It looked like a baseball mitt, and you're supposed to catch the asterisks.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, that's right. Humans are by far the hardest part of computer graphics because millions of years of evolution have given us dedicated brain systems to detect patterns and faces and infer emotions and intent. Because cavemen had to, when they see a stranger, determine whether they were likely friendly or they might be trying to kill them. And so humans...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We people in the world have extraordinarily detailed expectations of a face, and we can notice imperfections, especially perfections arising from computer graphics limitations. But it becomes by far the hardest problem.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So the MetaHumans effort is part of a decades-long initiative that Vlad Mostilovich, the most talented digital humans visionary in the world, has been working on for generations and generations of games.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
serving individual clients around the game industry for a while and then joining Epic as part of the three-lateral team, and leading now a worldwide effort to build all the technologies required to make digital humans realistic.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
One part is capturing humans, and so they've got really advanced dedicated hardware that puts a human in a capture sphere with dozens of cameras in them taking high resolution, high frame rate video of them as they go through a range of motions.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then capturing the human face is complicated because the nuanced detail of our faces and how all the muscles and sinews and fat work together to give us different expressions. So it's not only about the shape of a person's face, but it's also about the entire range of motion that they might go through.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Capturing one human requires a few hours of capture work in a dedicated environment like that, then thousands of hours of processing work to capture one. a precise and real-time replicatable version of that human in the environment. And so one of the things that's done is just capturing an actor or actress in the real world and then using them in a video game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That was my very first game. It took about a couple hours to build and tune, and I went from there. But I built a lot of things. I built... at different points. I built a programming language and a full compiler for a language like Pascal because I didn't know where you went to buy one of those. So I made my own. And one of the fun things of that time was bulletin boards.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But the much more interesting thing going on is capturing thousands of humans to form a data set whose goal is to encompass the entire range of faces in all of humanity. So going around every culture, every continent, every age, and every face of variety, and capturing representative people. So the entire range of faces is represented.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then being able to combine and merge those together to enable recreating an arbitrary face that the system's never seen before. So, you know, one of the ideas is capture giant amounts of this high-precision data, and then you use it to reconstruct a face at a consumer level.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Like maybe, you know, take an iPhone photo of somebody's face and then capture a very accurate depiction of that, not by synthesizing it then and there on that device, but by combining all the known details of human faces to accurately capture the most accurate representation of that image. So that's the data problem. There's a lot of other problems of computer graphics.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There's technology for rendering hair, which is really hard because you can't render every... Again, we know the laws of physics. It would be easy to just render every hair. It would just be a billion times too slow. So you need approximations that capture the net effect of hair on rendering and on pixels without calculating every single interaction of every light with every strand of hair.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's one part of it. There's detailed features for different parts of faces. There's subsurface scattering because... We think of humans as opaque, but really our skin as light travels through it. It's not completely opaque, and the way in which light travels through skin has a huge impact on our appearance. This is why there's no way you can paint a mannequin to look realistic for a human.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's just a solid surface, and we'll never have the sort of detail you see.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's right. Getting faces right requires the interplay of literally dozens of different systems and aspects of computer graphics, and if any one of them is wrong, your eye is completely drawn to that, and you find it on the wrong side of Uncanny Valley. So the level of perfection needed in this area is vastly, vastly higher than world rendering or grass or any of these other things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If the shadow is on a on a work of architecture slightly wrong, you're pretty perfect game, actually. Your brain doesn't really care that much, but if anything wrong with the human, it's totally jarring.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Before we had the internet in the hands of consumers, you used your modem and you dialed into a local phone number and connected to whoever was running the computer there. And every town or city had hundreds of these bulletin boards run by different people with their own personalities and themes.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
There are two main tools. Compared to the old days where every face was created by hand by an artist from scratch, one is the MetaHuman Creator tool for creating faces, where you have a huge number of parameters you can adjust to create a unique human by adjusting all the different capabilities of them.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You can then get that out of MetaHuman Creator into Unreal Engine, and then you can add all kinds of computer graphics features there in the engine. You could add clothing using the cloth simulation system, and you can adjust the hair and all these other parameters on the thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then there's MetaHuman Animator, a tool for animating a human based on a facial capture, which can be done on a device as simple as like an iPhone. and transfers the captured animation to the human you want, which is not straightforward.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If the actor has one face shape and the character on screen has another face shape, the translation that needs to be done from the actor to the face is actually really sophisticated and non-obvious. And if you just applied it literally, then it would be completely wrong from your point of view. So those are the main tools that people are using now.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then, went in the Unreal Engine, then you have a face and you can do absolutely anything you want to it. And you could also, if you decide to go outside of the metahuman geometry pipeline, you could build your own face, like any creature of any sort, and then use the animation tools to animate it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But yeah, this is 30 years into a project that's probably like 50 years in total to get to absolute photorealism and controllability for absolutely everything. So there's vast amounts of work still to do. And we don't feel like we've solved the problem at all. We've just given artists a big productivity multiplier and a quality multiplier. But this is not in a state that we would say is done.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, that's right. When you have an artist or actor in your studio and you're recording a specific performance, you can just capture their facial motion and apply it. But if all you have is a voice recording or you're generating a voice recording or it's parametric or procedural or AI generated, yeah, then you need...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so I spent a lot of time building a board and board program and learning how to deal with database management and user interface and dealing with multiple users concurrently and things. And so I probably found about 115,000 hours writing code just on my own as a kid between like age 10 and age 20 before I actually shipped a program to the outside world.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
the system to translate that speech, not only to movement of the mouth and lips, but also to facial expressions and the whole intent. When we're speaking, it's our whole face that's active and emoting in different ways. It's not just a mechanical motion of the pieces.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Lumen is a system for global illumination, meaning it's supposed to calculate the interaction of light with the entire scene in a way that mimics reality. The first generation of engines that did lighting just said, well, the light casts light and the surfaces it hits are lit and the surfaces it doesn't directly hit are dark. And that's just all the techniques we have. So you'd have...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
an area that wasn't hit by any light being completely black. But in reality, light bounces around the entire scene, um, dynamically. When a light hits a red wall, then, uh, Most of the blue and green light is absorbed, but the red light reflects off and now is hitting other things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so if you have a red wall with a white floor, light is bouncing off of the red wall into the floor, and now the floor is being turned red. And so the entire bouncing of light around the scene through multiple bounces is the critical challenge to solve here. And again, laws of physics are known, and so... The complete solution to this was written down in the 1950s, I think.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The real magic here in Lumen is this system that Daniel Wright developed over the course of many years, based on ideas formed over a longer period of time, to calculate the way lighting bounces around at different scales, ranging from the scale of miles or kilometers down to the scale of pixels and millimeters.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
and to not only calculate at each level, but integrate it seamlessly at each level to give the appearance of completely seamless and accurate lighting. And previous techniques were highly specialized, and artists had to make a decision for each light about exactly what it did.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And a lot of the practice with it right now is you build a scene, you place lights in it, and it just works to make it that much easier.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, that's right.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Light in the real world goes through a lot of bounces, and the effects of it are very subtle, but when they're not there, you miss them. Often a person can't point out why a scene is wrong, but they know it looks wrong, and it's the lack of the subtle lighting cues that we're seeing here.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, the industry's gone through a massive evolution and there's so many supporting systems to make this awesome. And always artists.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And you have to appreciate the algorithms are doing quite a lot here. You can have a scene with a huge number of not just lights, but also bright objects who reflect light off of them. Every one of those has to be captured in the reflections in order for it to be realistic. And you can't calculate every photon in the scene. And so you need really detailed approximations.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that's the field of computer graphics. It's about increasingly effective approximations of the laws of physics, which are just totally intractable.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Increasing capabilities and productivity, the limiting factor in every one of these businesses is cost. And the more the engine can make their jobs easier, the more power that brings them. One of the big revolutions we've seen in Hollywood is moving away from
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
doing computer graphics integration into a human scene with green screens, to moving to these large LED wall panels where they're displaying real-time computer graphics powered by the Unreal Engine. And that's a massive improvement in quality. You can recognize the old green screen movies because the lighting on the characters is just wrong.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, as much as they try to fix it up, it never really works. When you're filming in front of an LED panel with LED light emitters in front of you as well, the actor not only picks up all the lighting from the actual natural scene that they're supposed to appear in in the movie, but they also can look around and see it, and they're aware of exactly what set they're acting in.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And just the overall end result is that much higher. It's as much because the actors are able to do their jobs better, seeing the scene they're in, because the technology is enabling a better lighting calculation and a better interplay of virtual light and real-world light to make the end result awesome.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, you know, it's not just hours. It's really striving to learn, to understand what knowledge you have, what knowledge you lack, and to continually do experiments and work on projects that improve your knowledge base. And I didn't do this with a great amount of structure or planning. I was rather just going from project to project, doing things that I thought would be fun and cool.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think a lot of people in the industry are overly optimistic about the rate of progress of AI for video and other things like that. The real problem is consistency. Like, spurting out an image is really high quality. But with video, over the course of seeing all the AI approaches have consistency issues going from one place to another. And I don't think that those will just be remedied easily.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Fundamentally, AI just doesn't have anything resembling an understanding of the entire scene they're in, the entire arc of the movie or plot they're in, and the entirety of the world around them and how it might affect the scene. Whereas game engines have that exactly where they need to be.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so I think what we're going to see in the space of world-class high-quality productions isn't just everybody moves to AI and a large part of the human creatives contributing to that are obsolete, I think what we're going to see is AI becoming a multiplying force on the power of human creatives, making them able to create better stuff more quickly and with higher quality and results.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think unlike the fields of generative 2D art and generative text, I think the future of AI is much more complex and nuanced. And I think your interview with Mark Zuckerberg conducted in VR was a really good first example of this. So you did this VR discussion. It was capturing your faces and then rendering a completely 3D computer graphics model of your faces.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then the end result was patched up by an AI image enhancer that was able to add an awful lot of the missing subtleties that are lost by normal computer graphics rendering. And that's the first step. You can imagine the output of Unreal Engine being enhanced by an AI pixel shading post-processor is one thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You can imagine creation of objects being enhanced, especially mashing up high-quality objects that have already been created. Epic's Quixel team went around the world and scanned tens of thousands of real-world objects at extremely high levels of quality. They have everything from rocks to trees to archaeological finds and so on. all captured there.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And we have an awesome library of them on the fab content site. What's missing is the ability to create arbitrary amounts of new content. And I think using data like that and AI to create completely new trees that meet your specification from all of the knowledge that is built up of high quality scan trees, it's going to be a really valuable thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But, you know, I don't see this reducing the need for people or the role of people. Rather, I think it actually is probably an enhancer on that. I can't help but think when I go on Amazon and Netflix to watch a movie, there's an awful lot of linear content and most of it isn't very good because, you know, of the limitations of the media and the budgets and of other things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If we can use AI as an enhancer on that, then, you know, everybody's going to have even more opportunity than they have now. And every single technological revolution has changed the way that people work, but it's ultimately created more opportunity for people. And, you know, there are pundits predicting that this might be the last, but I think just the opposite.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I'm an optimist on this, and an optimist that it's going to create opportunity for everyone.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And with each project, I learned new things. learning about how to store and manage data, learning how to deal with advanced data structures, how to write complex programs that have deeply nested data and control flow. Each one of those provide a lesson which were later essential.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, I think that's the central challenge of the next decade of game engines and AI for content creation of all sorts. Because you have two very different models of the world that are emerging. There's the scene graph. The technical term we use to describe the set of all the objects in the world in a 3D world maintained by Unreal Engine or another engine.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, so in the videos you saw, it's the rocks and the trees and the snow and the bridge and the people and all of these things. And each one has enormous amounts of data attached to it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Some are like texture maps, some are sound files, some are animation files, and enormous amounts of detail all stored there in that procedure in this precise computer graphics representation that enables rendering it from any perspective with any settings and so on. It's a completely general...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
system that has complete context about the state of the world at any point and so you can always precisely reproduce it if you play the same scene 10 times in a row it's always the same it's never randomly changing you're like oh no why did that this character's face change midstream but it's also you know rather limited because you have to do build everything manually and it's costly and it's time consuming it requires expertise
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then you have this other model of the world, which is what AI sees or thinks. If we could peer into what's really happening and its parameters, there's something like the mushy connections of neurons in a brain. It has a vast amount of knowledge about the world and about graphics and about images and about people and about everything else.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's stored in a human incomprehensible form, but it can be extracted through queries, like asking it to produce an image from a prompt or a video from a prompt or whatever. But the huge problem with that is it's very mushy data. We don't know how to give it a command that will give us a precise result.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And if it produces one image one time and we change our prompts slightly, it might produce something completely different. We are unable to art direct it. And so it's this completely untamed tool. And I think, you know, when...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
When we figure out more and more ways to merge these and connect these two together, you can imagine AI enhancing the process of content creation in a traditional scene representation. You can imagine the scene representation being shared with the AI, so the AI not only sees the prompt, but also, here's a list of all of the objects in the world and their characteristics and so on.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It can learn more about how those objects should move and interact. So if you get a constant feedback cycle going back and forth between an engine and AI, then I think you can get the best of both worlds. Stable scenes, but also the higher productivity of being able to get content out. And the ability to select specific parts of it and art direct those.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And to have those art directions stick and be recognized as part of this permanent scene representation.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
In 1991, I released my first game, and over the course of that decade, we went from zero commercial releases to the first generation Unreal Engine. But this was largely just using the knowledge that I'd built up over the previous decade, just doing fun hobby projects. And if I hadn't done all of that work, there's no way I could have ever built the things that came later.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
This is certainly the most extreme example of it because AI is just so far ahead of prior technologies. But similar fears were had in every other industry. There's a fear that digital music synthesis would obsolete musicians.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And there's a very brief period of time in which songs with digital music instruments, like the early Minimoogs and Yamaha synthesizers, weren't allowed to win certain music industry awards because they weren't considered real music.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then, you know, over time, the people were educated and realized, oh, these are just instruments people are playing, and they're controlling them the same way they did before. There are similar questions about is, you know, computer art built in Photoshop really art? Or is it just, you know, goofy computer stuff? And, you know, I think nowadays, digital artists have gained respect, I think.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you look at just the tools that have existed in Photoshop, some of them are pretty sophisticated, and nowadays they have AI features. But I think AI is ultimately going to be another tool in the artist's tool set. I think it's going to become a more powerful, directable, and human-serving tool in the future.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And I think a lot of the alienation comes from the prompt either being immensely powerful at giving you an entire creation, but then being completely unwilling to let you control the nuances of it. That feels alienating. You give it an image, but you're like... replace this part of it with this thing, or make that object green, and it can't do it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Often it can't be convinced with any number of words in the prompt. And that makes it feel like the computer is taking control away from us, humans and artists, and is refusing to do what we want and has its own opinions. It feels like a competitor. I think when
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
When we have much, much, much more nuanced control of it, and artists can go in and just, you know, like, you know, let's enhance this object, do this, do that, do that, they'll feel it's, you know, like some of the tools that exist in Photoshop, which are in some ways compared to a paintbrush are superpowers already.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
AI will come to feel like that too, and will increasingly serve creators creating and enhancing a work in a way that feels just a natural extension of their own, you know, their own bodies and minds.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, there's a lot of complicated trends underway. It can be hard to break them down and distinguish them. I think a lot of people, like the theories that get the biggest traction on social media often don't capture the real underlying motive forces at play there. I think AI involved in code production will probably create a net benefit for the need for humanity to be involved in coding.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It may change parts of jobs. I don't think it's going to obsolete anybody who's willing to learn new ways of doing things. And it's always been this way. And I think that there's also a lot of overhype in AI. AI is really great at spewing out code that does something that a million GitHub repositories already do because it's kind of learned the underlying pattern.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's notoriously hard to get to do something new that hasn't been done before, especially when it's a complex task. And the bigger amount of code you ask AI for, the more it leaves you with just a mess of code that sort of works, right? And that's the problem with code. It's like 99% works, but the 1% might be harder to get to 100% with AI than with hand coding.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And everybody who's looking at this topic should actually try using the coding assistance on hard problems and see how they do there.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The topic of boilerplate code is an interesting one because the mere existence of boilerplate code is a failure of programming language and of the idea of creating software modules, right? You ask AI to create a sorting function, great. Now you have another sorting function that might be buggy alongside the million others that different people have written.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It would be better to have a sorting function that's been written and tested and optimized and everybody relies on it and More modular software, I think, will actually reduce the opportunity of AI because people doing programming work will largely be solving unique problems. They're actually hard problems in themselves and not just connecting other widgets.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, there were definitely karate kid moments. Because all this time I was learning math in high school and in college. I studied mechanical engineering. And so you learn all kinds of math, vector calculus and vector math and matrices and all these related fields, physics and stress and strain and how to deal with complex physical systems. And Yeah.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We're going to get shockingly close over the coming years, certainly less than 20 years. If you look at the progress, what areas where we have achieved total photorealism and what areas where we fall short, we're getting very close in all non-human interactions you see in the world, walking through a jungle or a city. All the lighting, it's very close, and that might be just a few years away.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But then all the problems that involve humans, human dialogue and intent, have a much, much, much higher bar that they need to meet to satisfy our brains and convince us that they're realistic or real. And I think that's going to be the primary challenge of graphics development and simulation development over the coming decade.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah. I was asked about this about 10 years ago, and I said that even if you gave us an infinite amount of computing power, we couldn't simulate realistic humans because we simply don't have the algorithms. We have no idea how to simulate human intelligence. And that was absolutely the case then, but... it's not really true anymore.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, what we're seeing with generative text AI is not only at a level that you could say that it's actually doing a pretty good job of simulating a human, at least humans at the text level, not at the emotional level yet, but at least at the level of words spoken and find more and more ways of training on more and more scenarios that, you know, you might have a very, very compelling human simulation going on in the next, um,
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
five years even. I'm not saying it's a good idea, but I think the arc of the technology is inextricably heading in that way, and it's heading at a shocking, shocking rate.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, absolutely.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, I don't think that these questions are necessarily unanswerable. I think I'd like to see more actual effort to ascertain what is the underlying mechanism of the universe. And I don't think we're here for no reason at all. I think the world's a pretty cool place.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the fact that we can exist and, you know, the laws of physics and especially the standard model of physics and all the parameters that lead to these atoms and life evolving in the presence of thermodynamic gradients, that's really cool. And I think it's a worthy field to study more about that holistically.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The question of are we living in a simulation ourselves always boils down to, well, if we are living in a simulation, what are they living in? Because at some point there has to be some base reality. Or one of the philosophical theories that was put forth seriously was that There is no physical reality.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I wasn't really sure how engineers would actually make use of that knowledge. Do you just like forget about it when you actually go off to do work? Or do you write down equations on paper? It was actually not clear as an early engineering student what you do. But when I started writing the first generation on real engine and I was dealing with 3D math, I was like, wait, I know this stuff.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you have a system of equations, such as the laws of physics, then all possible evolutions of dynamical systems under those equations kind of have a physical reality. So we just are kind of a manifestation of laws of math rather than needing an actual universe around us. I don't know. I like dabbling in that philosophy.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And as we get CAI becoming smarter and smarter and we get closer and closer to really capturing the full laws of physics, these questions become quite a lot more compelling.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So the whole idea of nested simulations, perhaps... Given sufficiently advanced technology, it's kind of mooted such that if you wanted to simulate another reality, you're kind of just actually creating the reality. You're doing quantum mechanical operations that would produce the same result anyway, and you're running them at full performance. So it's not really a nested simulation.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's just another thing that's happening in the universe.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So that would be interesting, but I think it's ultimately a theological question, and because it's no longer cool to deal with theology as part of science, there's not been much work on that. You can't publish results on those topics in a respected physics journal, so I think that's kind of been set aside.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But it's interesting to note that the laws of quantum mechanics themselves have a place for God or souls or whatever external source of input you might want to attach to such a thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that there's this idea of quantum wave function collapse, that when we look at a quantum system evolving in perfect superposition of many possibilities and you go to observe it, you actually just see a specific possibility. In the multi-slit experiment, the light ultimately ends up being observed going through one slit or the other.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And that's a place where there's this random number being injected into everything around us. trillions of trillions of trillions of times per second in everything we're observing. And if you want to attach some external input, well, there's a place.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I learned this. Yeah. And so suddenly, like the karate kid, you get to paint the fence and wax the car and suddenly put all the pieces together into a 3D engine based on a whole lot of accumulated programming language and math knowledge. Often knowledge gained without ever anticipating that I might use it in that way.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah, it's funny. In that area, we know nothing more than cavemen knew whatsoever. We know the laws of quantum mechanics, and we have computers that may be soon more advanced than we are. But we just don't have any answers to the fundamental questions about life, the universe, and everything.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, I think the technology is coming. And then there's a human question of should we go that far?
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Certainly as a game developer ourselves, Epic doesn't aspire to that. We make fun games. And the ultimate manifestation that we found is fun games that people play together to have fun in between work and the other things in their real lives.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But as the simulations get more and more realistic and the capabilities become more and more real, I think we have to ask ourselves some hard questions about how should humanity operate in that space? What are the limits that we should go to and what are the limits we should set?
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Yeah. You know, I think the thing to appreciate is, like, game developers have just generally been on the good-spirited side of things. If you look at the worst things that people do in popular video games today, it's like, what, Uraba Bank and GTA? It's clearly fictional and all and fun and not serious and over the top. You know...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think, yeah, as things get more realistic, especially simulation of humans, yeah, there are some hard questions that will have to be answered there. But I think the thing that all game developers need to remember is we're here to make people's lives better by entertaining them, providing them with fun and a diversion from other things and being a part of
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
of their lives and not not trying to be too big or too being too much and not trying to provide an alternate to reality but to just provide a fun source of entertainment like the many other things that people do uh do for fun so uh you've spoken like i mentioned about the metaverse for many years let's step back what is the metaverse and speaking of fun uh you know fortnite
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, the metaverse is an idea whose stock price goes up and down depending on who says what on what day. And some have an ability to drive it way down by opening their mouths. But ultimately, this is about multiplayer social gaming experiences. You and your friends getting together in a 3D world and having fun together in any way you want.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you're playing Fortnite Battle Royale, in my view, that is capturing the essence of the metaverse.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And especially in Fortnite, when we got Sony on board so that all players on all platforms in Fortnite could play together, could voice chat together, and could be part of a single game experience, it really took on a new nature, which was not just like a multiplayer game with heritage from Doom, but also a true social experience between you and your friends.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And Fortnite Battle Royale is just one manifestation of that. Another one is like Rec Room VR, where you're standing around in VR with friends playing billiards or shooting hoops or doing other light entertainment things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think every game that has a huge number of players who play together socially as part of their entertainment lives, I think is really getting at the core essence of the aspiration for the metaverse. And we're still in the very early days of it. I was on the internet in 1992 or so, and it was a pretty bare-bones thing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think when we look back at the state of gaming today, we'll realize that there's a lot further to go to get to the ultimate version of it. But I think it's all on track, and I think
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It was the time we released Fortnite Battle Royale and started playing together all of the people at Epic and Squads and experiencing that world that we realized that this trend was afoot and that we needed to do everything we could to bring in other creators so that anybody could pile on to the work we were doing by creating their own worlds through Fortnite Creative and UEFN and
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
and creating more games and more genres that people could play and ever expanding the repertoire of fun.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Well, Fortnite has humble beginnings. In 2011, we'd just been in the final days of finishing one of the Gears of War games, and... We wanted to explore ideas for new games. And we had a general idea that we would like to build some smaller games, online games, in order to learn more about that space and not just have one single massive game in production at all times and only one.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so everybody in the company was given a week to form a team and work with whichever co-workers they wanted and build a game. Using Unreal Engine. So you can actually build something pretty interesting in a week. And one of the teams built the very first version of what became Fortnite.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
The very first version of it had a different art style, but it had the idea at the core that you're going to build forts by day using this building system. Then night would come, and you'd defend the forts against zombies. And the longer you could go, the more elaborate forts you could build, and the more survival waves you could withstand, and it would get cooler and cooler with time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And, you know, that game was in development for a very long time. We always saw the potential. Just the building aspect of it was incredibly fun. But we made different pivots at different times. At one point, we moved to the current Fortnite art style away from kind of more of a realistic style. Made it, you know, more in the Pixar vein of, you know, cool stylized characters.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's right, and constantly striving to make connections between these fields and look for their applications. Long after I chipped on Unreal Engine, it was like going back through an engineering textbook and looking at, oh, yeah, I used that, I used that, I used that. And then I got to the section on eigenvalues. I'm like, I don't know what the hell this is.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
People come to Epic because they want to work with the best people in the world. Artists bring a lot of different personal art aspirations and style capabilities, and many of them are very multi-talented. It can produce photoreal content or highly stylized content.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And a lot of the best artists on Fortnite were a lot of the best artists on Gears of War to change styles but continue doing awesome work. We'd realized that Fortnite could be really mainstream and it could be a game people play for a long time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That was the goal. So, you know, a few of the artists got through and defined the new art style and we moved to it. And at different points, it evolved towards being kind of like a light MMO, like Destiny, with rather complex RPG and stat systems. And that evolved into a, you know, kind of an MMO-like tower defense game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
MMO only in that persistence of items and stats, you know, which became Fortnite's save the world mode. Yeah. which we launched in early 2017, and it was a moderate success. It paid its budget, and we'd come out ahead. And then at the same time, the Battle Royale genre was booming. PUBG had just come out. Tons of people at Epic were playing that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They were like, oh, this would be so cool if it had Fortnite building. And so we assembled a team in a war room, you know, like 30 people in one big room. And, you know, they worked insanely hard for four weeks to build Battle Royale. So the nice thing is all the content for Fortnite had been built over the previous seven years.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
They had a huge library of content, but no gameplay of the type they wanted. So they had to build it all in that four weeks and ship it and... That put Epic on an exponential growth curve where we went from 300 employees to thousands of employees and went from about $100 million in revenue to billions of dollars in revenue and became the center of the gaming world at the time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Since 2012, we've been building online backend systems to support player accounts and login and all of the different systems that are needed to make a multiplayer game. And we've been building them to be scalable. And by some miracle, we built them stably enough that they were able to scale up.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
But, you know, it turns out eigenvectors and eigenvalues were the critical breakthrough that made the Google search engine technology work and stand apart from the rest because they found if you threw all the links that exist in the web and, you know, links from and to different sites and you put them in a giant matrix and you found the dominant eigenvalues, then those eigenvectors described the best search results for different things.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so the online team was responsible for patching that code, spent a year of intense work getting it to scale from like 40,000 concurrent users to 15 million.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
concurrent users yeah i mean they're scaling they're scaling that's a lot that's immense but they'd done such an awesome job of building the foundations that uh it was tractable it was doable if it if they hadn't done that then the company would have died you know fortnite just wouldn't have been playable and the whole thing would have failed i mean there's just so much detail there that makes all the difference because i mean uh that's what spotify has talked about that
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You know, the trend nowadays for building online services is microservices. There's not one big server that handles all the interactions with Fortnite. There's game servers running 100-player game instances for each Battle Royale session, and then there's... an account server and many instances of it all talking to a shared database.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And there's hundreds of different microservices talking to each other. And so scaling is a matter of identifying what are the bottlenecks in that system and making sure that each one can scale and has enough redundancy to be able to handle the load. Thank God for Amazon Web Services and cloud hosting, because Epic went to 15 million concurrent users without buying any server hardware.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We were able to Just call up Amazon and say, we need more. And there was a period of time there where Fortnite was undergoing this exponential growth, and we'd find, like, one week we ran out of servers in Brazil during a heavy weekend of play, and next week we had an even heavier weekend of play, and there were servers to handle it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Like, somebody at Amazon had dropshipped, you know, millions of dollars of server hardware to... into Brazil and turned it on just in time for fortnight to need it. Um, and you know, there are a lot of unsung heroes, uh, in that story. Many of them we've never heard of.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Fortnite makes billions of dollars a year. And that's the majority of Epic's revenue. We have a robust business around Unreal Engine licensing, Rocket League and Fall Guys, and some other tools like the Fab Content Marketplace. But the majority of it is Fortnite.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Because we've chosen to reinvest heavily in building what we think is the future of technology, we're spending more every year than we're making. And for a bit of time, we were spending over a billion dollars a year more than we were making, and we found that to be unsustainable, and we went through some painful layoffs at that time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And then we stabilized, and now we're spending several hundred million dollars a year more than we're making, which we can very well afford to do because we have billions of dollars in the bank. thanks to a combination of the profits we made when we were a very small company with a very big game, and because of the investment we've raised.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And so constantly... Picking up knowledge and looking for ways to put it together is the thing to do. And if you aspire to be a programmer, you've got to write a lot of code and you've got to continually learn new things and improve. If you want to be an artist, you've got to continually draw artwork of all styles and all kinds and constantly push yourself to learn more and more.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We're not an oil well pumping oil out of the ground where we discovered oil. We are growing to be a future technology powerhouse, and we think the 3D space and the future real-time 3D simulations is going to be one of the major facets of technology for humanity, and we're all investing in that.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
That's right. We're a company that can start working on a project knowing that we won't reach fruition or make any money from it at all for three years, four years, five years. We're totally okay with that. And that's the cycle that's fueled our growth over time.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
It's constantly investing in the future and being a serious company that's doing serious R&D side-by-side with shipping and maintaining products and earning money from them.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Let me start with the present of gaming and why it sucks.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Fortnite is an awesome thing. You go into Fortnite, there's 100 million monthly active users there. A huge number of your own friends are there. You can play with them. Go from experience to experience seamlessly without leaving the app. There are 100,000 different islands you can play on, and some of them are really awesome. And there are constant new ones coming out and constant things to do.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you want to play Roblox, you quit out of the Fortnite app, you launch the Roblox app. Different program, different friend system, different account names. Your username in Fortnite and your username in Roblox are different names, and they're not connected to each other. So you have to remake all of your friends and then find different...
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
you know, things to play, and now the controls are different, so you have to relearn how, you know, the joystick, mouse, keyboard, controller works in that experience, and you have to go from place to place, and you buy some stuff in Fortnite, and it's really cool, and you can use it anywhere in Fortnite, and then you go in Roblox, and you don't have that stuff.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
You have to buy different stuff, and that stuff only works in Roblox, and same with Call of Duty. It's another isolated place. And same with World of Warcraft, and same with League of Legends, and every other, every place you go is its own unique place, different friends, different account names, different people, and there's no social cohesion between them at all.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And a long time ago, consoles set out to solve this problem by creating their console-wide friend system and accounts. your friend on PlayStation in one game is your friends on PlayStation in another game. But only on PlayStation. If you're on Xbox, you can't see PlayStation friends. And so you have two basically orthogonal and cross-cutting divisions of the world into fiefdoms.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Because you never know exactly what you're going to end up doing in the long run, but the more knowledge you have and the more skills, the more chance you have putting it together and being successful.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
which were not created with bad intentions, but arose and are separated, isolated islands. One is the platforms and their social services, Xbox, PlayStation, Nintendo, Steam, Epic, if you add it to the list. And the other is these different games people play.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And because of this weird historical artifact, we're left in a world where people can't seamlessly move from games to games, bringing their friends and their stuff. So the solution to this is to federate and connect all of the systems together.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
All of the players on all of the different platforms can be recognized by their name and put the at sign in it so your Xbox names and your Fortnite or Epic names and your Steam names can all live together and interoperate together in a single space. So unifying the social ecosystems is one thing that needs to happen. The next and bigger challenge is to unify the economies too. Now,
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I'm not talking about a sword you have in World of Warcraft should work in Fortnite. Every game is going to have its own gameplay rules, and a lot of games are going to have stuff that only works in them. But there's a huge set of games that have in common the idea of a cosmetic system that does not affect gameplay outcomes, but is purely cool looks and cool appearances.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
Most of the major multiplayer games have them. And If you look at games, you could probably bundle together about 70% of them and say they're similar enough that they could actually interoperate. You could own an outfit in Fortnite, own an outfit in Roblox, and own the same outfit in maybe Call of Duty, and maybe 100 or 200 other games, and actually expect they would work together.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And you find other kinds of items are probably under-operable, too. Fortnite has car outfits, so you can buy different appearances of a car. And when you find a physical car in the world of Fortnite, if you're the first person to get into it in that session, boom, it takes on your chosen car appearance. cosmetic, and now you have a cool car that's identifiable as yours.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We realized early on with Fortnite that the key to making Fortnite work as a creator economy was to open up the revenue from the item shop to all the sources of engagement. There are two big things happening in Fortnite that make it work as a product and as a business. One is the game modes, Fortnite, Battle Royale, and all of the user modes and everything else are sources of engagement.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I found getting an engineering degree and then never working in an engineering field, just being a computer programmer, was immensely valuable. Yeah, I went to University of Maryland, which for some disciplines, it's kind of known as a party school, but they work the engineers to death, worked really hard.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
People play there because it's super fun. And because they're playing there, they're willing to buy cool stuff to make their character look cooler. And so you have all these sources of engagement, but the sources of engagement don't make money directly. You can't spend money in Fortnite Battle Royale to buy a game item. The gameplay is not pay to win, and it's all just a game.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
So we make money from the item shop. And the item shop only exists because of the sources of engagement. If you weren't playing Battle Royale, trust me, nobody would want to buy a Fortnite outfit. If you weren't playing any Fortnite games, why would you buy Fortnite outfits? And so you have all the revenue in this item shop economy and all the engagement in this engagement economy.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And the thing that magically makes the Fortnite creator economy works is revenue sharing. Item shop spending according to sources of engagement by engagement.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
If you buy an item and you've played, you know, 40% of your time in Battle Royale and 60% of your time in these user modes, the money you spent, the portion of that that's profit can be separated out and paid out to all the different creators who participate in that economy. And that's why Fortnite scaled up to a $400 million creator economy so far and is growing. It's amazing.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
One of the really critical things we aim to do in designing that is ensure it's a creator economy that could scale to other companies, other ecosystems.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
and say, right now we have many industry standards bodies, one standardized game ratings, age ratings of games, another standardized file formats for the web, another style standardizing file formats for 3D, like chronoscopes in the metaverse standards form. If we had a standards body standardize what are portable outfits in games, game outfits that you could buy in one game that work in another,
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
What are their dimensions and what are their capabilities and what can you do and what can't you do and so on. Then you could have an item economy where every game agrees to respect each other's item purchases of that sort. And revenue is shared between ecosystems as well. That would be incredible.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And if you learn any engineering discipline, you learn massive amounts of math and you learn the rigor of problem solving, you know, not just what you find from the Wikipedia article, but going through all the exercises of solving complex problems and building up series of solutions to derive an answer. It's valuable and it embodies the knowledge that you need as a programmer.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
I think this can be done. Um, yeah, we did a lot of analysis of the fortnight economy and found that, um, Some Fortnite experiences correlate with higher spending than others. And Battle Royale is relatively strong in that area because you see your character from behind and see all of your other characters from the front.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
And you have lots of opportunities to really see who you are and to interact with other players. And a lot of games have that characteristic. One funny anomaly stood out. There was this game that was one of the big breakthroughs in Fortnite, only up. It's a game where you're just climbing up and up by following paths of stacks of objects and things. It was just stupid fun. Everybody loved it.
Lex Fridman Podcast
#467 – Tim Sweeney: Fortnite, Unreal Engine, and the Future of Gaming
We found people weren't spending a lot of money on outfits when they were playing only up. It's kind of intuitive, actually. You're not seeing other players. If you see anything, you're seeing their butt as you're trying to catch up to them, jumping from object to object, and they're above you. And so it wasn't a mode that showed off outfits very much.