NVIDIA Shows Interactive Ray Tracing On GPUs

MojoKid writes "During SIGGRAPH 2008 in Los Angeles, NVIDIA is demonstrating a fully interactive GPU-based ray tracer. The demo is based purely on NVIDIA GPU technology, and according to NVIDIA the ray tracer shows linear scaling during rendering of a complex, two-million polygon, anti-aliased automotive styling application. The article reproduces screenshots from NVIDIA's demo. At three bounces (rays being traced as they bounce three times through a scene), performance is demonstrated at up to 30fps at HD resolutions of 1920x1080 for an image-based lighting paint shader, ray-traced shadows, reflections and refractions running on four next-generation Quadro GPUs in an NVIDIA Quadro Plex 2100 D4 Visual Computing System." Meanwhile reader arcticstoat passes on Intel's latest claim that rasterisation will die out the next few years, possibly in favour of ray tracing.

Comments

Beautiful

[AKAImBatman]

Wow, those screen caps are gorgeous. I hope this finally puts to rest the idea that rasterizing with upteenth number of features added in can compete with the image quality of Raytracing. While rasterizing may have a number of competitive features, it's hard to get the same level of specularity, reflection, shadows, shading, and other features so nicely demonstrated by this demo.

The genius of what NVidia is doing here, I think, is that by using their existing GPU architecture, they create a path by which Raytracing can be phased in as a technology without removing the support and investment in current rendering pipelines. This is a bit different from Intel's goal, which appears to be a cutoff between the old and the new.

Another interesting point is that this demo is currently capped at 3 casts per pixel. Which means that the scenes shown could look even better than they already do. Shadows could be softer, reflections could be more complex, and inventive scenes could be created to make for interesting styles of gameplay. (e.g. Fighting in a hall of mirrors.) If 3 casts/pixel is the baseline, then NVidia is setting up a vast new territory for graphical improvements. Each increase in casts/pixel will increase the realism of the scene. Thus graphical quality becomes a matter of raw horsepower. A market that I'm sure NVidia would gladly be interested in opening up.

Funny how things change, eh? :-P

Actually, I doubt NVidia has changed its position by very much. They're probably making a smart business decision and ensuring that they ride the wave of Intel's hype. If Intel *does* succeed in convincing the market that Raytracing is the future, NVidia will be ready to compete rather than cede the market.

Re:Beautiful

[Colonel Korn]

They're probably making a smart business decision and ensuring that they ride the wave of Intel's hype. If Intel *does* succeed in convincing the market that Raytracing is the future, NVidia will be ready to compete rather than cede the market.

It's great for nVidia that they can do this with their chips, but I don't think this was done primarily for tech purposes. I think you're close to the truth when you say they can ride Intel's hype, but not quite spot on. I think this is meant to break Intel's growing ray tracing hype machine, not come along for the ride.

"Look, we can do now what you say you'll do in two years, and we can do it WAY better than you will be able to then, but on our current tech."

I can't imagine anything could be more effective at ending the "Intel will crush nVidia with ray tracing" meme that's been affecting nV stock.

Re:Beautiful

[hr.wien]

They are gorgeous? Really? I think they look distinctly average. The lighting calculations look very simplistic. Yes, the shadows and reflections may be pixel perfect, but that just doesn't matter that much. You usually can't tell they are anyway. The same scene rasterized with a simple cube map for the car's reflection and some proper shadow maps would look much better. Not to mention run faster.

And "graphical quality becomes a matter of raw horsepower"? This unlike in rasterization then?

Re:Beautiful

[ChronoReverse]

What on earth? How are those overly shiny objects beautiful in any way?

The technology is probably better than that but the actual screenshots are distinctly ugly for this day and age.

Re:Beautiful

[mypalmike]

Every bounce casts a new ray, so "3 casts per pixel" is an accurate description.

Re:Beautiful

[hr.wien]

Sure you can. A human instinctively knows when something looks "right" or "wrong".

Yes, and amusingly reflection and refraction (two of the main benefits of ray tracing) are a couple of things that humans generally can't tell if are being fudged. As long as it's in the ballpark it's enough to fool the human eye. Pixel perfection is way beyond what's required.

And one of the reasons why rasterization is capped is due to lighting problems.

What does that mean? Capped?

Lighting technology has improved significantly in the last decade, but still not sufficiently to compete with raytracing. Raytraced lighting will look more natural to an untrained viewer.

Why? Details please. What exactly is more realistic about tracing each pixel through the geometry than drawing the geometry directly in the appropriate pixels? The underlying lighting calculations are the same either way, meaning they will both look the same, so the only real concern is speed for any given scene.

So if we look at speed ray tracing only has a real benefit in reflection and refraction, but that's not really a winning argument because, as I said, people can't really tell if it's 100% accurate anyway. I sure can't. Ray tracing can also do accurate soft shadows relatively easily, but the ray count required makes that completely unrealistic in real time for the foreseeable future. Shadow maps will be faster either way, and look 99% as good.

Ray tracing is simple to implement, but so is cracking a password using brute force. That doesn't make it the best solution.

Re:Beautiful

[Austerity Empowers]

I think if you look closely you'll see that they used materials very sparingly. The man behind the curtain (IMO) is that they're dedicating all their GPU and memory bandwidth to ray tracing computations, at the expensive of traditional raster manipulations.

Who cares? Well, I think if you're playing a game where you are free to run where you like, you may care.

I agree, nVidia is showing that ray tracing doesn't scare them at all. And when it's ready to happen, it will. I disagree that it's ready to happen any day now.

Re:Beautiful

[Anonymous Coward]

The screenshots look relatively ugly because of the hashed-together-demo quality of the environment textures. But it's not a texture demo, it's a raytraced lighting demo.

Bare in mind this is ray tracing at a very rough and ready stage, but the potential is enormous. If you want to see the sort of effects it can achieve, check out some professional 3DSMax/VRay renders.

There's a nice render here for illustrative purposes.

That's just a single frame with high quality textures, but it surely shows the potential.

Re:Beautiful

[jacquesm]

It isn't. More casts per pixel means that more rays are cast at slightly different angles through each pixel, and those are then averaged to yield the actual pixel colours.

Three bounces per ray simply means that a single ray can bounce three times before it's colour values are known.

Re:Beautiful

[robthebloke]

I say rasterization sticks around 3-5 years.

I used to hear exactly the same things being said by the ray-tracing evangelists in the FilmFX industry 15 years ago. Rasterization is still the primary techinique used for any film you care to mention, and I'm almost 100% certain it will still be the primary technique 30 years from now.

Re:That's a nice canned post ya got there

[Anonymous Coward]

The kind with a star next to his name, obviously.

don't quit your day job quite yet

[Ancient_Hacker]

The devil is in the details. Ray tracing with glossy surfaces is relatively easy. But if you want to simulate real-world textures like orange-peel, bark, hair, or skin, things can really slow down.

What a waste of resources

[rogerbo]

I just looked at those pictures and then checked a high res shot of Gran Turismo 3 Prologue on a PS3:

http://o.aolcdn.com/gd-media/games/gran-turismo-5-prologue/playstation-3/22.jpg

I don't see enough of an improvement to increase GAMEPLAY in any significant way. The reflection maps and shadows that are created by the current rasterization tricks are good enough that you suspend disbelief.

I'd much rather the increase in GPU power be used through a GPGPU API for artificial intelligence, advanced physics simulations, fluid dynamics, flocking behavior or other things which could really add to gameplay.

A few extra reflections and slightly softer shadows???? I won't even notice and neither will the average gamer.

Re:What a waste of resources

[jamie]

I kind of assumed the big win was that game development gets easier. If your game is rendered by ray-tracing can't you spend more time on building the models, lighting and gameplay and less on fine-tuning rendering tricks?

Re:What a waste of resources

[Big_Breaker]

The gameplay improvement is in deformable physical environments. Combined with mainstream physics engines, raytracing would allow for a sea-change in gameplay by allowing interactive gaming environments.

Raster methods rely on a bunch of tricks, many of which need to be precalculated for static maps. The most obvious example is binary space partioning tables. This leads to very static feeling environments that disallow interaction beyond doors of various types and moving platforms.

Re:That's a nice canned post ya got there

[Colonel Korn]

Story submitted: 11:00am. Your post submitted: 11:00am. There's just no way in hell you formulated a response and typed out all of that in less than a minute. So just what kind of douchebag are you, anyway?

Uh, maybe he looked at the story on the firehose.

Of course, but when?

[MojoRilla]

Of course ray tracing, or one of its decendants, like photon mapping, will end up dominant. The question is when. Ray tracing is used now for rendering movies like Cars, which are probably pretty much state of the art for computer graphics, and would be used for things like PC games except that is so computationally expensive.

As to when rasterization will be replaced, the short answer is not any time soon. The article's title is misleading. It says "Intel: Rasterisation will be replaced in five years", while Intel's ray tracing guru Daniel Pohl actually says "Looking ahead five to ten years from now, I believe that rasterisation will be used less and less in games". Big difference there.

So, I think this will progress quickly, but we won't be getting rid of rasterization any time soon.

Still waiting...

[Ukab the Great]

I want NVIDIA to come out with a card that gives boring DOOM clones intriguing plots and compelling gameplay.

What this will mean for games

[Tibor the Hun]

Like someone said a few months back, now all the games will be composed entirely of shiny balls, toruses, and checkerboards.

Re:What this will mean for games

[CaseyB]

Don't forget teapots!

Re:That's a nice canned post ya got there

[jacquesm]

You're just sore that you didn't get to annoy a lot of people with your frist post or gnaa rubbish.

Re:That's a nice canned post ya got there

[xerxesVII]

Um, he's fucking Batman. He can do all kinds of stuff.

That's nothing. Cell can raytrace a whole city!

[Funk_dat69]

Speaking of Ray Tracing...

Check out this video showed at SIGGRAPH this week of the University of Virginia Rome model being ray traced in real time by a Cell Blade:

http://www.youtube.com/watch?v=YZnbMWy9A0Y

Nifty!