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

[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.

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!