Gadgetory

hey everyone I'm joined by Tom Peterson at Nvidia and we've done a few talks with Tom before so today I think we're gonna talk about about r-tx and rate racing in general as a concept so r-tx obviously I think announced at GDC GDC that's right explored more here at GTC and let's do a let's do kind of the elevator pitch okay Bret for ray-tracing so the basics before that this video is brought to you by EVGA and the X 299 dark motherboard for the Intel high-end desktop CPUs the X 299 dark is one of the only mother boards on the market with proper vrm cooling we've tested this and found a significant performance increase over those without active cooling on the prm's this board was used in our recent attempt to set a top 10 record in fire strike and you can learn more about the x29 dark at the link in the description below you're telling me before we went on camera this has been the Holy Grail since it is it's before you were born absolutely well before even Brian was born right yeah so ray tracing is is actually changing from well I'll call like an artistic artistic version of creating images to more of a physics version of creating images so today with rendering not many people know but most of that is kind of like an artist painting a painting there's lots of heuristics and you know you do things like texture colors and what you're trying to do is find a mathematically simple way to generate an image that's pretty compelling so you have geometric models you have shader programs but all these things have no connection to the real world right ray tracing is completely different and by the way that old method of kind of using computer approximations has artifacts you know things like the shadows don't look right or things Sparkle there if they're getting better and they've always been good and and they're great for gaming but they're not real ray tracing in contrast is trying to do a physical simulation of light and the way to think about it is you know we live in a world where light bounces all over the place and it hits on an object and bounces around diffusing deflecting subsurface scattering that's all kinds of stuff right but eventually one ray of light makes it into your eye and and hits your retina and that's what we perceive as vision so what ray tracing is all about is pretending that you're kind of modeling how a retina works and you project forward into the into the scene trying to figure out what other rays have hit the object that's lighting your eye so ray tracing is all about the physics of light and when you do that you get rid of all this artistic interpretation that happens with traditional renderings yeah so it's very it's very much the way movies do generating CGI and now what's really different is that we're able to do that in real time using r-tx right yeah well we we've done some ray tracing renders and not real time right and to get everyone up to kind of a an example for scale before this video started we'll have about a two-second intro animation that rolls that intro has some ray tracing in it and it's I think it took us over two weeks to render the two seconds right 120 frames Wow so is that the logo spinning cut that is yeah you know yeah so obviously that is not a not great for real time no coming down to real-time then I guess for RTX do you have any idea how many how many samples were taking or how many rays are being traced yeah well it's all different depending on you know the the platform that you're running on but the key thing to RTX is we have to make some simplifications with even our next generation hardware Volta it's still not enough to simulate every ray I mean obviously we live in a continuous world there's there's too many rays to simulate so you have to kind of have a heuristic that simplifies the problem a little bit and then you need techniques to make that simplified ray tracing experiment look good so we have filters that are built into our game works that effectively make simplified ray tracing or sparse ray tracing look really good and that's the key as technology gets faster as our GPUs get faster we'll be able to do more sophisticated ray tracing with more Ray's and get more phone arista photorealistic over times so right now it's all I think all the demos have been done on Titan B's revolted anyway yeah is there a is there a hardware or architectural limitation that prevents it from right on Pascal or is it is it just a raw speed thing yeah it's it's a speed thing I mean there are there are Hardware widgets inside of Volta that accelerate ray tracing you know you can you can do software back offs on older generation GPUs but they're they're a lot slower so at the end of the day real-time ray tracing is going to be reliant upon optimized hardware to accelerate that search of the space was was Volta built specifically with this in mind of accelerating ray tracing or was that was another I product one of many things that I had to does well right so ray tracing for us has always been something that we're super passionate about super interested in and it takes many generations many years and you know this like from our comput computer you've got to start somewhere and we're gonna make it better over time and Volta was the place where it really got its first big investment and it's gonna get you know increasingly competent increasingly better over time across more of our product lines when when dealing with Ray J's and then so we've talked about sampling so how many samples you do how many rays you trace there's also denoising right so what why do we need denoising again it's about that sparseness of current hardware capability so if we could simulate every ray accurately in a game you would need anything knowing you would have a completely continuous image generated from ray tracing but the truth is today on our hardware that's too expensive so what we actually do is generate a sparse image and that has little pops of simulated pixels adjacent to things that didn't get simulated so what the denoising does is runs deep learned filters on that to make it look a little bit more natural and that denoising technology is tightly coupled into you know what's your algorithm what's your what's your technique for picking race this in right reflections and refractions were also a big part of some of the demos yeah what mates let's talk kind of a general concept level on a hardware side what makes it difficult for GPUs to deal with reflections refractions or like we saw the one demo the Star Wars demo where you had sort of almost an infinity mirror effect right guns reflecting off the body off the gun yep so what makes that specifically difficult well it's really hard to simulate unless you're simulating the light reflections itself the truth is on GPUs today with traditional renderers you're not really simulating reflections you're generating a texture and then you're warping the texture all at once and you're kind of painting it onto a surface so that you can kind of get the impression of a reflection right but what's really hard about that is you have to you can only do that kind of with one immediate bounce if you start thinking about things reflecting on things reflecting on things then with traditional renderers you're generating these these images and then you're kind of transforming them on the surfaces and then re transforming that thing onto the next thing so it's the order of what is bouncing on a lot that gets very very complicated so that that's why it doesn't normally look very good or do very well on traditional renders ray tracing is completely different because it kind of goes backwards from your eye and it says what is my eye seeing and then what are the set of things that hit that eye so you can actually accurately calculate the the order that things are getting lit so we have a scene with the camera with the player and we have let's say one source of light like direct source of light the Sun or something like that where we tracing rays from in the sea and they is it coming straight from the light source so the way to think about it is to go from your eye you're actually going just coming out of the camera that yes so you say I don't need to simulate every bit of light in the scene what I really need to simulate is what light is going to hit my eye and so you start from there and say which pieces of geometry are are relevant to my current camera position and let's go figure out the color of those things and so now you know a collection of points that need to get lit and you can see what light sources are bouncing into that thing and it's just this tree that mushrooms out very quickly right here refractions is there anything special with refractions versus reflections and it's all just physics right it's just model the thing that you're you're interacting with accurately so if you have parameters built into your model that affect how light transmission works it all just works that's the best thing about ray tracing you don't have to special case everything you just sort of build your your physical model accurately and then the visual effect is just a result of calculations and I guess for the immediate future still kind of using traditional techniques raster in conjunction with ray-tracing for purposes of complexity I guess it's all computation right so for the short time being I think you're gonna see a lot of hybrids where maybe global illumination is done with traditional techniques and then you could do shadows or reflections or you know other other focused effects using ray tracing and I think you'll see those hybrids for some time before you know we get to the point where our hardware is more capable and you'll you'll convert wholesale to a different technique for current iterations of the r-tx stuff I guess you guys working with Microsoft for DirectX yes implementation I saw there was is was there some Vulcan news as well there's we did announce anything but the way to think about RT X is it's more of the layer that is the Nvidia layer exposing our hardware software capabilities up to AP aughts so DirectX takes advantage of RT acts and in the future other os's or other api's could do similar stuff right what's going on on the game engine side what are the when you hand this off the epic games what do they have to do for implementation I suspect you know I'm not really sure exactly what its gonna do but obviously we're working very very closely for ray tracing with all the game engine guys and I suspect you'll see adoption over time and we have game works which is intended to deliver a complete ray tracing solution to make it easy for integration both into games and game engines right cool anything from all the coverage you've seen of RT x ray tracing in general any other key points you want to bring that I think people have gotten wrong or have overlooked I think everybody gets it that it that it dramatically improves the fidelity of names and it's it's new and exciting it's kind of the Holy Grail and to me it's just a question of how much time is gonna happen before we start seeing real games that are taking advantage of it and we're doing everything we can to accelerate that obviously so the next step I guess is getting it off of dgx requirements basically right not to more consumer hardware yeah I mean if we want to see a big adoption of ray tracing technology we need to get it out into them into more platforms right right there'll be the future that may be yeah you know it's hard to say okay a lot of lot of things going on there cool well I guess we we might do some additional conversation after this if you find anything interesting here check the article links Lee description below I'll do follow-ups on any additional questions people have in the comment section if you have anything major and thank you guys always Tom yeah right man great see you soon we'll see you all next time