Real-Time Ray Tracing : Holy Grail or Fools’ Errand? *Partial Reconstruction*

[Davros]

that hardware raytracer, maybe nv will buy them then incorporate it into their gfx cards like physx ?

[Arnold Beckenbauer]

Caustic Graphics Ray Tracing Acceleration Technology Review
Opinions?

[Scali]

The obvious area is in films – much of the Pixar film work is ray traced as are most of the final high-quality visual effects done in Hollywood.

Prior to Cars, Pixar used virtually no raytracing at all, and neither did most others in Hollywood (many of them use Pixar's Renderman software). And even in Cars, the majority is still rasterized, the raytracing only accounts for about 20-25% of the total scenes.
So most of Pixar's film work is not raytraced.
I can't stand this fallacy that has been used to promote raytracing for ages.
Dreamworks has published a nice paper on lighting in Shrek arguing how they don't even WANT to use realistic light models because they are hard to control for an artist. Relatively simple lightsources are much easier to control than a completely accurate radiosity solution and all that. You simply place lightsources where you want the light, just like in regular movies.

[Simon F]

I think the major exceptions to this rule are "Ice Age" etc. IIRC we used to have someone from Blue Sky on B3D who used the tag "Mr. Blue".

[trinibwoy]

Originally Posted by Arnold Beckenbauer

Caustic Graphics Ray Tracing Acceleration Technology Review
Opinions?

Interesting concept but anything requiring custom hardware that predictably will have little developer support isn't going to make it on its own. For this to be workable you would have to design your engine/game around the Caustic hardware and API.

[MfA]

Oh, so they finally admitted they had no silicon I see.

My opinion ... if they had a world class renderman engine they could immediately sell which they could accelerate they'd have a product, an accelerator for software which doesn't exist will be hard to sell.

[Ike Turner]

Originally Posted by MfA

Oh, so they finally admitted they had no silicon I see.

My opinion ... if they had a world class renderman engine they could immediately sell which they could accelerate they'd have a product, an accelerator for software which doesn't exist will be hard to sell.

Eh ? What?

[homerdog]

Originally Posted by MfA

Oh, so they finally admitted they had no silicon I see.

Does an FPGA not count?

Originally Posted by MfA

My opinion ... if they had a world class renderman engine they could immediately sell which they could accelerate they'd have a product, an accelerator for software which doesn't exist will be hard to sell.

Originally Posted by PC Perspective

Caustic is already working with companies like Cinema4D, Autodesk, Blender Render and others to begin implementing support for the CausticGL software into future versions of these rendering applications. If they can achieve a near-global adoption of their software then selling the acceleration hardware to design companies would be an easy sell. Caustic did purchase a company called “Splutterfish” that created the Brazil Rendering System in order to better understand how to work with software ISVs to integrate CausticRT and develop tools to utilize the hardware and software capabilities.

So I guess they're working on that. Sounds they aren't trying to make inroads into interactive graphics 'till a few year down the road. The closest they expect to get to gaming in the mean time is in building "pre-baked" assets with their ray tracer.

[MfA]

Originally Posted by Ike Turner

Eh ? What?

Are you questioning my admittedly atrocious sentence structure?

[MfA]

Originally Posted by homerdog

Does an FPGA not count?

No it does not ... hell, they didn't try to hide the fact that they were using FPGAs initially for nothing. For the cost of a couple of those huge FPGAs you could build a rendering cluster of COTS hardware which would blow it away. Which will be a significant problem for them even after they do have their own silicon (due to low volumes). Maybe they can sell it on power consumption ...

[rpg.314]

Aren't they allowed to even prototype initially? :-/

[MfA]

It's not a prototype, they are selling it ... and they shouldn't have allowed their PR staff to try to hide it was a FPGA.

[Betanumerical]

Originally Posted by MfA

It's not a prototype, they are selling it ... and they shouldn't have allowed their PR staff to try to hide it was a FPGA.

Its a prototype for developers.

[digitalwanderer]

That they're selling?

[hoho]

Originally Posted by Arnold Beckenbauer

Caustic Graphics Ray Tracing Acceleration Technology Review
Opinions?

They use 8 CPU cores and at least 2 FPGA's and can't reproduce stuff that people are doing using the same amount of CPU cores and zero FPGA's. Their only hope is that the next version will have insane scalability and can do much more work on the die so that CPU won't be a bottleneck any more.

[Scali]

This article gives some insight in how these cards are used:
http://www.extremetech.com/article2/...2345640,00.asp

Apparently the chips are used to accelerate some portions of the raytracing process, but the actual shading is done on the CPU (and in the future can be done on the GPU).
It seems that their hardware mainly reorders rays so that they can be processed efficiently in parallel by conventional CPUs and GPUs. They use the word 'scheduler'.

[Heinrich4]

Originally Posted by Scali

This article gives some insight in how these cards are used:
http://www.extremetech.com/article2/...2345640,00.asp

Apparently the chips are used to accelerate some portions of the raytracing process, but the actual shading is done on the CPU (and in the future can be done on the GPU).
It seems that their hardware mainly reorders rays so that they can be processed efficiently in parallel by conventional CPUs and GPUs. They use the word 'scheduler'.

Thanx for posting this article.

Finnaly one of first steps going to RT... im pray here for some day we could see a mature hardware (or hybrid with Raster...) doing true RT(60 to 200 rays/pixel).

(what level opemRT /saarcor guys going in your RT engine? It does exist today?)

[Scali]

A similar article on Arstechnica:
http://arstechnica.com/hardware/news...g-platform.ars

Also, the business plan is apparently to start with these FPGA-based cards (Caustic One), because they're cheap to build... then build an ASIC card (Caustic Two) if there is enough demand.
Because the chip doesn't really rely on tons of bandwidth and tons of parallel SIMD processing power (those things are basically delegated to the CPU or GPU performing the actual shading and other tasks), it doesn't have to be a very big, cutting-edge chip. They want to build the ASIC on 90 nm, running at about 350 MHz, which should be more than 10 times as fast as the current FPGA.

[Joker B]

A curious business case in that article about game level design. Secret Level made a level lighter that was GPU based. Big win. Otavio Good showed at @ XNA game fest a couple of years ago: http://www.secretlevel.com/downloads...in%20Games.zip

What's not clear here is why a raytracer would be a better choice... unless it was used slowly for AO or something like that. And you'd still have to write the software and integrate it into your pipeline.

Or just buy Beast.

Natural lighting isn't what's usually desired. Look at the average live-action movie crew. The big lighting trucks contain a few lamps and a LOT of equipment (and people) who are there to PREVENT natural light. Believable, yes. Natural, no.

[PhilTaylor]

[QUOTE=Joker B;1289243]

What's not clear here is why a raytracer would be a better choice...
QUOTE]

some effects are just easier with a tracer.

reflections and refractions are pretty trivial in a tracer and are much, much harder to get right in a triangle engine.

cubemap reflections, for instance, dont typically have an accurate point of view for all camera positions as the cubemap is rendered from one pov.

and who knows, might even affect gameplay if done accurately in a tracer

[MfA]

Originally Posted by Joker B

Natural lighting isn't what's usually desired. Look at the average live-action movie crew. The big lighting trucks contain a few lamps and a LOT of equipment (and people) who are there to PREVENT natural light. Believable, yes. Natural, no.

Interactive games are fundamentally different because the viewpoint tends to be arbitrary.

[Scali]

Originally Posted by Joker B

Natural lighting isn't what's usually desired. Look at the average live-action movie crew. The big lighting trucks contain a few lamps and a LOT of equipment (and people) who are there to PREVENT natural light. Believable, yes. Natural, no.

Exactly, I read a nice paper from Dreamworks a few years ago, about the lighting used in Shrek, and how they like to control the lighting accurately with simple pointlights or spotlights, rather than going for GI/'physically accurate' solutions.

[Arnold Beckenbauer]

800TFLOPS Multicore IC for Realtime Ray Tracing

800 TFLOPS and we have real-time Ray Tracing.

[MfA]

Really limited ray tracing on an extremely inflexible architecture ... what a throwback.

14400 FP multipliers in a 150 Million gates ASIC is impressive though, but the amount of memory available on chip is incredibly small ... I just don't see how you are ever going to implement say GI algorithms on that thing.

[rpg.314]

Obviously, it is aimed to solve a verrry specific problem.