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NVIDIA Shows Interactive Ray Tracing On GPUs

Posted by kdawson on from the raster-fair dept.

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.

11 of 260 comments (clear)

  1. Beautiful by AKAImBatman · · Score: 5, Interesting

    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.

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    1. Re:Beautiful by Colonel+Korn · · Score: 5, Interesting

      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.

      --
      "I zero-index my hamsters" - Willtor (147206)
    2. Re:Beautiful by WilyCoder · · Score: 2, Interesting

      "Another interesting point is that this demo is currently capped at 3 casts per pixel."

      You mean three bounces per pixel.

      Also, from TFA:

      "running on four next-generation Quadro GPUs in an NVIDIA Quadro Plex 2100 D4 Visual Computing System"

      Sure this is impressive, but they are pushing kilowatts to get this kind of performance.

    3. Re:Beautiful by hr.wien · · Score: 4, Interesting

      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?

    4. Re:Beautiful by hr.wien · · Score: 5, Interesting

      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.

    5. Re:Beautiful by AKAImBatman · · Score: 2, Interesting

      What is efficient enough to be feasible real time is.

      Yet in the case of Raytracing, "efficient enough to be feasible" means real shadowing, not the shadow-map crud we see in most video games.

      Can you honestly tell me you think the shadows in Nvidia's demo look better than the ones in, say, Crysis?

      I can and I will. Shadow maps used in games like Crysis beat you over the head with depth perspective. i.e. "Look, there's a shadow! Now you know how far off the ground the helicopter is!" While that's nice and all, only the objects that you map and define to have shadows actually cast a shadow. The subtle interactions of the environment and the actors are usually lost. It's almost like someone took a bunch of stage props, covered a stage with styrofoam sand, then threw all the props on top. Thus the actors stand out from their environment.

      With ray tracing, the shadows are correct. Period. If a monster picked up that NVidia car and threw it through the air end over end, you'd see all kinds of shadow interactions happening that simply won't be visible on a shadow-mapped engine like Crysis.

      Heck, you don't even have to get that complex. The car casts shadows upon itself. Which already makes it look more realistic on a closeup than anything an existing game engine can do.

      In addition, ray tracing can scale a hell of a lot farther when it comes to realistic lighting and shading. With more rays not only comes softer shadows, but multiple shadows, reflective surfaces, and other "realistic" shadowing techniques that can't be touched by today's shadow map engines.

      --
      Javascript + Nintendo DSi = DSiCade
    6. Re:Beautiful by afidel · · Score: 2, Interesting

      No, for illustrative purposes of what ray tracing is capable of you have to look at something like this, it's very very close to being indistinguishable from a photo. That took 21 hours on a P2-350 (465 MFlops) so on a GTX280 which is ~3,000 times faster it would take about 45 seconds to render, not exactly a playable framerate. We're a few doubling of transistor count away from being able to do photo-realistic ray-tracing at playable framerates.

      --
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  2. Not quite yet, I'm affraid by Moraelin · · Score: 3, Interesting

    Actually, I think that the biggest problem with animated porn isn't texturing-vs-raytracing, but the models and animations. Last time I ran into some adult Poser-fu, it looked all wrong in a massively uncanny-valley way, and not because of the texturing.

    And with the animations, well, I'd assume it's actually easier and cheaper to find a gal who'll bounce on a cock for half an hour for a few (thousand) bucks, than a highly skilled artist and animator who'll make that look natural.

    Plus, raytracing is IMHO entirely the wrong secret sauce there. Ray tracing works best for sharp, metallic/mirror reflections. Because then you can take each ray and reflect it as one ray. If you want to go diffuse, that's a lot more expensive with ray-tracing. Then you need to split each ray into sub-rays that reflect into slightly different directions from there. Same as anti-aliasing is done by calculating sub-pixels, basically.

    I.e., ray tracing looks grrreat and is the cheapest for shiny cars, crystal cups, and the like. Which is why everyone ray-traces cars and the like. It sucks for something like human skin, unless, of course, you want to make those humans look like polished shiny plastic dolls.

    So, well, I can't imagine that much need for it in porn at the moment. Unless, of course, you want to make a Transformers sex movie. Or maybe one with liquid- metal Terminators fucking. (Hey, they must have made some female versions too, right?;)

    --
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  3. I, for one, welcome our ray traced overlords by caywen · · Score: 3, Interesting

    I think raytracing is going to be the only way to go in 5-10 years. As poly counts go up, average poly size is going to drop below 1 pixel, and the overhead of tracing rays will match the overhead of rasterizing tiny polys + scene overdraw, etc. Of course, what I fear is that all the games will start feature too much reflection on every surface, because they can.

  4. That's nothing. Cell can raytrace a whole city! by Funk_dat69 · · Score: 4, Interesting

    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!

    --
    FUNK!
  5. The one thing I want by Chemisor · · Score: 2, Interesting

    > But reality is that several best games I have played were ... 2D.

    Damn right. And you know what capability I would really like to have on a card? Masked blit. That is the single most time-consuming operation on all 2D games. If you could copy all your tiles to the video card memory and then maskblit them onto the visible page (or blit and flip if it's too slow), that would really make 2D games smooth as silk and leave more CPU power for AI and real gameplay.