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Students Evaluate Ray Tracing From Developers' Side
Posted by
timothy
on Wed Jun 25, 2008 05:01 PM
from the do-not-look-at-ray-with-remaining-eye dept.
from the do-not-look-at-ray-with-remaining-eye dept.
Vigile writes "Much has been said about ray tracing for gaming in recent weeks: luminaries like John Carmack, Cevat Yerli and NVIDIA's David Kirk have already placed their flags in the ground but what about developers that have actually worked on fully ray traced games? PC Perspective discusses the benefits and problems in art creation, programming and design on a ray traced game engine with a group of students working on two separate projects. These are not AAA-class titles but they do offer some great insights for anyone considering the ray tracing and rasterization debate."
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What's the point ... (Score:2)
I know this may not be a popular question, but what is the point with raytracing for games?
We're finally getting to a level of technology with rasterization where we're producing visuals at a level which is "Good Enough" (or better) for practically every genre. Do we really need to get on the hardware treadmill for the next 10 years to get to a similar technology level to get slightly more realistic lighting and reflections?
Re:What's the point ... (Score:4, Insightful)
Yes, we do because everything that we do currently is just a hackish like system where we are using programing tricks and other methods to get it to look realistic. Instead of a video card you would just need a faster cpu, which if we base off of moore's law won't be much longer.
Parent
Re:What's the point ... (Score:4, Interesting)
Instead of a video card you would just need a faster cpu, which if we base off of moore's law won't be much longer.
If the video card makers had picked up on the RPU [uni-sb.de] you could use your video card to get realistic high frame-rate raytraced games today.
Dr Slusallek is working at nVidia now, so who knows?
Parent
Re: (Score:3, Interesting)
Re: (Score:3, Insightful)
Indeed. Who cares about raytracing? The next big thing in games is procedural generation of content!
Re: (Score:3, Insightful)
Raytracing is just as much of a hack as rasterizing. It's just a different hack. Both are nothing but rough approximations of the rendering equation.
Raytracing is better at rasterizing for rendering silver spheres on checkerboards, but the lack of those aren't the main problem with graphics these days. Raytracing is pretty much as bad at rasterizing at things that matter much more, such as decent global illumination.
Re: (Score:2, Insightful)
Raytracing is an "embarrassingly parallel" task that should scale well as desktop computers execute more and more code in parallel. Can the same be said about rasterizing?
Re: (Score:3, Interesting)
Actually, yes ...
One of the main reasons that we now have 800 stream processors on fancy graphics cards is that you can split the most costly portions of advanced rasterization into hundreds of independant processes.
Re: (Score:3, Informative)
Actually, no.
Rasterization is not embarrassingly parallel in the same way that raytracing is. Distributing tasks among those 800 "stream processors" is exceedingly complicated, because the underlying "task" involves iterating over every pixel that intersects with a given triangle rather than (as in raytracing) iterating over every triangle that could intersect with a given pixel.
-:sigma.SB
Re:What's the point ... (Score:4, Interesting)
The point is that, in raytracing, you can assign each of your 800 "stream processors" different pixels. Done. You're parallel. When one finishes, give it another pixel to work on, and repeat until you've rendered the whole thing.
Each core still has to iterate over all (well, some, I'm oversimplifying) of the triangles, but it can do so COMPLETELY INDEPENDENTLY of the other cores and still come up with a good result. Your performance gains are almost linearly proportional to the number of cores.
You can even have a relatively high-latency connection (Gigabit Ethernet, for instance) between the various cores, broadcast the scene data over this connection, and then receive individual "chunks" of rendered pixels back. I defy you to do that with rasterization.
-:sigma.SB
Parent
Re:What's the point ... (Score:5, Insightful)
Realistic lighting allows you to use those clever algorithms in your head that you've learned over the past 20+ years in the real world, so when you see a flicker of a reflection or a change in the shadows in a darkened tunnel you can turn and blast the damn camper on the opposite rooftop before he nails you with his sniper rifle.
Parent
Re: (Score:3, Informative)
But raytracing doesn't do realistic lighting at all!
It does more realistic lighting than rasterization, and it definitely will do caustics... you just need to shoot more rays. Whether you can shoot enough rays in realtime or not, well, that's where you need the speedup from an RPU.
"Global Illumination" isn't a lighting effect, it's a heuristic for rasterizing that fakes some effects that require additional rays to calculate. In some cases that's ludicrously many rays, in others it's not. There's also some v
Re: (Score:3, Informative)
Now read everyone else's responses and realize that raytracing is a super-easy way to take advantage of multiple cores and simplify your code at the same time. All the crazy stunts and tricks you have to pull to get some of those lighting and reflection tricks can be thrown out the window, and the extra time could be used to
Re: (Score:3)
Honestly, I'm not that impressed with the raytraced Quake Wars. Some nicer textures and higher res models could make it a lot prettier with a lot less horse power. Yes, the reflections are impressive, but reflections aren't that important really.
Re: (Score:3, Interesting)
All the crazy stunts and tricks you have to pull to get some of those lighting and reflection tricks can be thrown out the window, and the extra time could be used to ::crosses fingers:: make better gameplay.
Not only that, but any weird new kind of gameplay which depends on interesting visuals can be done much, much easier.
Simple example: Portal. Right now, it involves all sorts of crazy tricks. As I understand it, objects (at least, cubes which fall through the portal) are duplicated at both ends of a portal (in case you can see both ends at once)... The "hall of mirrors" effect of two portals across the hallway from each other is apparently intensive (it causes lag), and there is a hard (adjustable) limit,
Debate? (Score:5, Informative)
"...ray tracing and rasterization debate"
I don't think there is any debate at all, RayTracing is by far superior, there is just the problem of computing power.
Anyone (perhaps ask the modelers for the games) who deals with 3D software, knows the benefits of RayTracing for simulating reality (Reflections, Ambient Occlusion, Sub-Surface Scattering, etc)
And once computing power reaches that level it will even speed up the process of creating games because you can let the RayTracing take care of shadows, reflections, highlights, etc instead of manually mapping them.
Take a look at anything LightWave [newtek.com], Maya [autodesk.com], 3Dsmax [autodesk.com], Softimage [softimage.com], Blender [blender.org], etc spits out of its render engines, or visual effects in recent movies... granted, that's (as stated a few times in the discussion) years away... but, I don't think anyone is arguing against RayTracing.
(-1 Bastard) ...but...whatever, ive been waiting for real-time RayTracing for years even just within my own 3D applications, nevermind games...
I'd quibble. (Score:5, Insightful)
Typically, however, games manufacturers do NOT mean "raytracing" when they say "raytracing". They mean basic rendering. ie: Applying of shaders and other simple colouring techniques. Renderman, the rendering package used to produce movies like Finding Nemo, uses rendering, not raytracing. Rendering is popular with movie producers because it's fast and "good enough". (Audiences differ on the subject, with plenty of people preferring model-based special-effects because the lighting is real and the reflections are correct - well, they'd better be!) My fear is that true raytracing and physically correct lighting models will be totally overlooked in favour of things that will be cheaper to produce and therefore make more money.
Parent
Re: (Score:3, Insightful)
You already have raytracing in games, just not in realtime. Why spend the computing power in realtime raytracing when you can bake the static lighting into PTMs (polynomial texture maps), or the dynamic lighting into spherical harmonics maps, and use these to reconstruct the illumination, including self-shadowing effects, with convincing effects, at a fraction of the cost?
Lightmaps already take into consideration ambient occlusion, check q3map2 for instance, this is nothing new. As for reflections, no one w
Re: (Score:3, Interesting)
Just because CPU power is at the point where it may be enough, the whole point to having a video card is to offload that work to allow the CPU to deal with "more important" work. Console games tend to be very limited in terms of what is going on around the main character in a game. Sure, the graphics may be an issue, but you don't see games where the main character in a story has to push through a crowd of computer controlled NPCs that are not just there as a part of some puzzle, but are all doing or tr
Re: (Score:3, Informative)
None of the programs you mentioned is a pure ray tracer. All of them can be used to make images which involve ray tracing, but a lot of great work has been done in those programs without tracing any rays. So, probably not the best example
Re:Debate? - Dont forget TrueSpace (Score:3, Interesting)
I know fully well 3DSMax and Maya are the defacto standard in big shop game developers. Blender is HUGE among open source in indy game shops.
But the "other" underdog is TrueSpace. I've been with them (Caligari) since version 1. They're now at 7.6. In the almost 10-15 years they've been around they've always been under one guy, Roman Ormandi. It says a lot to me, that he hasn't yet "cashed" out on this amazing 3D hand changing that's been going on with all the other apps.
3DS started with Autodesk, went to Di
Re: (Score:2)
Rasterization is the process taking some object or model that is precisely defined and placing it on a screen made of components. Because of this ailiasing occurs.
That's kind of a non-point. Rasterizing and aliasing happens all the time with standard television signals. But I have no problem distinguishing between a rendered actor (a "synthespian") and a human actor. It's not the aliasing, it's the full complement of lighting, shading, texture, model, physics, motion, etc.
And even if you could perfectly render flesh, hair, cloth, etc., to the point where I couldn't see the difference in a static image, there's still the problem of motion. Human gait is still m
Re: (Score:2)
Re: (Score:3, Informative)
Art Direction (Score:3, Insightful)
Seen them? Good. They demonstrate one thing very effectively: no matter what rendering engine you use, good art direction trumps technology, every time.
These games are using "cutting edge" technology, and the article blathers on about how ray-tracing allowed them to use ridiculous amounts of triangles and have "complex lighting and shadows." But they look like crap.
Contrast this with games like Twilight Princess, Super Mario Galaxy, Ico, Shadow of the Colossus, and Rez. All of them use rasterization on hardware between two and eight years old, but they look fantastic.