NVIDIA Doubts Ray Tracing Is the Future of Games

SizeWise writes "After Intel's prominent work in ray tracing in the both the desktop and mobile spaces, many gamers might be thinking that the move to ray-tracing engines is inevitable. NVIDIA's Chief Scientist, Dr. David Kirk, thinks otherwise as revealed in this interview on rasterization and ray tracing. Kirk counters many of Intel's claims of ray tracing's superiority, such as the inherent benefit to polygon complexity, while pointing out areas where ray-tracing engines would falter, such as basic antialiasing. The interview concludes with discussions on mixing the two rendering technologies and whether NVIDIA hardware can efficiently handle ray tracing calculations as well."

Counterpoint

Kirk should talk to Picard [demoscene.hu] who is quite enthused about real time raytracing.

Re:Counterpoint

That lends a lot of weight to the raytracing argument, since I generally prefer Picard over Kirk...

Re:Counterpoint

Yes, I loved the episode where Odo shape-shifted into a layer 3 switch during the Romulan invasion.

Re:

As a counter-counterpoint, the article has quite misleading pictures-

The Ray-Tracing images are super slick, but are non real-time, highly processed work.

Whereas the comparison Rasterized images are real-time, game-generated examples. If you were to all

Re:Counterpoint

We're not talking about the current technology, we're talking about the future. As in whether Ray Tracing is the Future of Games.

Graphics hardware has evolved into huge parallel general-purpose stream processors capable of obscene numbers of FLOPs per second... yet we're still clinging tenaciously to the old safety blanket of a mesh of tesselated triangles and projecting textures onto them.

And it makes sense: the industry is really, really good at pushing them around. Sort of how like internal combustion engines are pretty much the only game in town until alternative save themselves from the vapor.

Nvidia, either by being wise or shortsighted, is discounting ray-tracing. ATI is trailing right now so they'd probably do well to hedge their bets on the polar opposite of where Nvidia is going.

3D modelling starts out in abstractions anyway with deformations and curves and all sorts of things that are relatively easy to describe with pure mathematics. Converting it all to mesh approximations of what was sculpted was, and still is, pretty much just a hack to get things to run at acceptable real-time speeds.

Re:Counterpoint

From what I read, I think part of this is nVidia assuming GPUs still stay relevant. If we ever do get to a point where raytracing -- done on a CPU -- beats out rasterization, done on a GPU, then nVidia's business model falls apart, whereas Intel suddenly becomes much more relevant (as their GPUs tend to suck).

Personally, I would much prefer Intel winning this. It's a hit or miss, but Intel often does provide open specs and/or open drivers. nVidia provides drivers that mostly work, except when they don't, and then you're on your own...

Re:Counterpoint

Nvidia, either by being wise or shortsighted, is discounting ray-tracing.

What you may not realise is that NVIDIA sells a renderer/raytracer which uses the GPU for accelleration, targeted at the animation and VFX market.

They are not discounting ray-tracing. They are embracing it. And they know, from lots of their own R&D, that it's not going to be competitive in the real-time market at any point in the forseeable future.

Steve Jobs also uses this trick

Saying something sucks if he's already developing a product for it.

Relief Texture Mapping

A good way to mix both techniques is Relief Texture Mapping [ufrgs.br]. It's a good way to get smooth surfaces thanks to the texture interpolation hardware, with no extra polygons.

Re:Relief Texture Mapping

It can do curved surfaces, but is far from perfect and really is an approximation placed into a polygon structure (the surface itself is flat, but you don't see the surface itself). The silhouettes are done using 4 of the 16 quadrics as a reasonable subset to get an estimate curvature (4 to save on storage). These are pre-calculated and therefore have some overhead (either in a file or dynamically calculated on load). It is also restricted to hard shadows because it works similarly to ray tracing - tracing lines, not patches (it's hard to describe that, but think of it like when light hits an object, it reflects a line, not a cone), however, you get these shadows for free.

Incidentally, Steep Parallax Mapping and Interval Mapping also use pseudo ray tracers, but the surface curvature is unique to Relief Mapping (the quadric technique doesn't work with them). Most other techniques can be adapted to support soft shadows, however, and most game developers I know (3 professional) think soft shadows are more important than curved surface relief maps. If surface curvature is important, they'd rather tessellate it out.

Like we were expecting something else

Seriously though, does anyone expect Nvidia to say, "Yes, we really do think that our products will all be obsolete and outdated in a few years. Thank you for asking." I personally have no idea as to whether or not ray tracing is the future of games, but I really don't think that Nvidia is the right person to ask either, (just as Intel isn't).

Re:

Seriously though, does anyone expect Nvidia to say, "Yes, we really do think that our products will all be obsolete and outdated in a few years. Thank you for asking." I personally have no idea as to whether or not ray tracing is the future of games, but

Re:Like we were expecting something else

So instead of buying a separate chip for graphics, you get the same performance boost from just getting a second CPU or one with more cores.

Not only that; you get a performance boost from your server. And from your kids computers. You get a performance boost from your HTPC. And potentially any other computer on your network.

The highly paralellizable nature is the most interesting aspect to raytracing IMO; with distributed engines one could do some very cool things.

Re:Like we were expecting something else

Actually, I don't think that's true at all. Raytracing, just like today's rasterizers, can greatly benefit from dedicated hardware for doing vector operations, geometry manipulation, and so forth. This is particularly true as raytracing benefits greatly from parallelization, and it would be far easier to build a dedicated card with a nice fat bus for shunting geometry and texture information between a large number of processing units than it would be to use a stock, general multicore processor which isn't really designed with those specific applications in mind.

Besides, the whole reason to have separate, specialized gear for doing things like audio/visual processing is to free up the main CPU for doing other things. Heck, we're even seeing specialized, third-party hardware for doing things like physics and AI calculations, not to mention accelerators for H.264 decoding, etc. As such, I see no reason to move graphics rendering back to the main CPU(s).

Re:

From what I can tell, Ray-Tracing is closer to 'reality', and so you'd expect the technology eventually to tend in that direction.

Not necessarily, humans aren't that picky that the virtual reality be a perfect reality. For example, I don't ever expect to pick up a laser, find a thin enough slit and see the quantum effects on the wall, not the real simulated deal anyway. More natural

Hmmm - who to believe, who to believe??

Intel says to do it with the CPU, and nVidia says to do it with the GPU. What a surprise.

Obey your thirst...

Personally, I prefer spites to either ray-trace or polygons. I still thing Starcraft (the game, not the conversion van) had some of the best graphics. But then I am kind of a fuddy-duddy. I also think River Raid was an awesome game.

Re:

I still remember, as boy in the early 80's, getting the opportunity to take a cruse on a navy ship. Seeing the targeting equipment on that ship gave me a real appreciation for just how realistic the graphics on Missile Command were. They were darn near i

What do the people that make the software say?

What about game and engine devs? Where do they see the future going?

Re:

What about game and engine devs? Where do they see the future going?

IAAGD. My current paid project is to have both a raytracing module and a rasterizing module, and is designed to use them completely interchangeably. Personally, I'm a much bigger fan of r

Re:What do the people that make the software say?

I am an game-developing 3d-artist, and our biggest problem right now is the lack of ability to render complex per-pixel shaders (particulary on the PS3). But this is only a short-term problem, and what would we do with the ability to create more complex shaders? Fake the appearance of the benefits of Ray-tracing (more complex scenes and more realistic surfaces) of course!

On the other hand, the film industry could be a good place to look for the future technology of computer games. And as it is right now, it's preferable to avoid the slowness of raytracing and fake the effects instead, even when making big blockbuster movies.

Probably right on this one...

For the most part, I really don't see ray-tracing adding much to the world of gaming that isn't being handled well enough by current methods. Unless someone was specifically creating games that somehow directly incorporated either the benefits or the added calculations involved with ray-tracing itself, it would only be a costly, and highly inefficient gimmick of an alternative to current techniques.

Sure, ray-tracing has its place in a lot of areas, but real-time gaming would be a terrible misuse of processing horsepower... especially when you could be applying it to other areas of gaming that actually affect gameplay itself. For example, how about more robust AIs for in game elements, or high-end physics processing that can combine things like fabric/hair/ fluid/fire physics processing with the ability to decimate objects completely as vector-calculated chunks based on the surrounding environments, rather than all this predetermined destruction we currently see in games. (Example, a surface could be eroded incrimentally by having a fluid running acrossed it until a hole forms in the shape of the fluid path...)

Hardly anything new

For years, the movie studios were using Pixar PRMan, which is in many ways a high-quality software equivalent of a modern graphics card. It takes a huge and complex scene, divides it into screen-space buckets of equal size, sorts the geometrical primitives in some way, and then (pay attention now!) tesselates and dices the primitives into micropolygons about one pixel each in size (OpenGL fragments, anyone?), shades and deforms them them using simple (or not-so-simple) algorithms written in the RenderMan shading language (hey, vertex and pixel shaders!) and then, it rasterizes them using stochastic algorithms that allow for high quality motion blur, depth-of-field and antialiasing.

Now the latest part is slightly easier for a raytracer, which can cast a ray from any place in the scene - of course, it needs this functionality anyway. But a raytracer also needs random access to the scene which means that you need to keep the whole scene in memory at all times, along with spatial indexing structures. The REYES algorithms of PRMan needs no such thing (it easily handles 2 GB of scene data on a 512 MB machine along with gigs of textures), and it allows for coherent memory access patterns and coherent computation in general (there is of course some research into coherency in raytracing, but IIRC, the results were never that good). This is a big win for graphics cards, as the bandwidth of graphics card RAM has never been spectacular - it's basically the same case as with general-purpose CPU of your computer and its main memory. But with 128 or so execution units of modern graphics card, the problem is even more apparent.

Unless the Intel engineeers stumbled upon some spectacular breakthrough, I fail to see how raytracing is supposed to have any advantage in a modern graphics card. And if I had to choose between vivid forest imagery with millions of leaves flapping in the wind and reflective balls on a checkered floor, I know what I would choose.

A matter of speed

"C is much too slow, to get good performance you must use assembly."

"Scripted languages are much too slow, to get good performance you must use compiled languages."

As computers get faster, there is always a move from technologies that are easier for the computer to technologies that are easier for the developer. Since ray tracing involves less hacks and is a more direct model of the effects developers want to create, it seems inevitable.

Re:A matter of speed

Current methods do not scale parallel. SLI does not give you 2x the resolution at the same framerate, or double the framerate at the same resolution. Same for any sort of quad SLI solution (two dual chip gfx cards, etc).

Ray tracing scales almost perfectly. The same processor with 4 cores will perform about 3.9x as well (pushed pixles per second, so either higher FPS or higher resolution, or a mix) as one with 1 core. This is why intel is pushing this.