NVIDIA working on hardware acceleration for Mental Ray and ray tracing

[jujubee]

Sorry Thomas if we offended you - I guess many of the people here are just simply excited to see the new technologies.

Good luck on FR and other developments - competition can be healthy competition!

[JeffG2]

It seems slow, and with only 3 teapots? well I think from them we can see a version say 5 years from now?

Dude!

I just got a project to render three teapots!

I could really use that kind of app!!!

[davidr]

vray RT is very impressive. However I think in the long run GPU based acceleration is going to win the race. Unless some new cpu comes out that outperforms the GPU. Nvidia just has too much money at its disposal to throw towards this and, eventually they are going to develop a bridge...

Why can't Vray leverage both CPU and GPU? I'm sure they both have intrinsic advantages, such as particles rendered by GPU.

[davidr]

Vlado and Peter (as well as the rest of the Chaos team) has repeatedly provided the BEST support of any software I've seen and constant updates (as well as letting some of us try their betas) for all these years. They diodn't charge for a single update.

And the fact that Vlado responds personally, even in threads at the Area, etc, make me suspect that there's more than one Vlado, or that software is really really easy to make.

[davidr]

GPUs and pure raytracing are not very happy a couple atm.
Try Gelato on the most powerful GPU of today, and make it raytrace, and it will be EXTREMELY slow, even compared to a middle-weigth cpu.
But try and do other things with it, like motion blur or DoF, and it is a zillion times faster than the fastest of CPUs doing it through raytracing techniques.
For instance, try to do a DoF preview, or Moblur preview from a max camera.
That's the kind of speed GPUs at the moment can offer, if very selectively.

Why should Gelato raytrace off the GPU? why not simply have a bunch of if/then to target the most appropriate hardware available, so CPU for raytrace, GPU for DOF, particles, etc? Sounds pretty simple, anyway (as long as I don't have to do it).

[jreynolds]

Actually it's both :P

Since software is so easily written Chaos spends all their time and money on upkeep of the alien tech regeneration chamber used to reproduce Vlado

--Jon

[jreynolds]

Why should Gelato raytrace off the GPU? why not simply have a bunch of if/then to target the most appropriate hardware available, so CPU for raytrace, GPU for DOF, particles, etc? Sounds pretty simple, anyway (as long as I don't have to do it).

Unfortunately, lacking a tool to monitor GPU usage I've not been able to determine what stages of the render process are using CPU vs. GPU. If it's the case that Gelato primarily uses the GPU for raytracing, like you suggest, it is most likely because all dev time in the past was spent on GPU accelerated paths and trying to generalize the whole thing. In using Gelato I have found that it does like CPU time also... but who knows maybe it's because Nvidia sells GPUs and not CPUs

--Jon

[vlado]

Why should Gelato raytrace off the GPU? why not simply have a bunch of if/then to target the most appropriate hardware available, so CPU for raytrace, GPU for DOF, particles, etc? Sounds pretty simple, anyway (as long as I don't have to do it).

I think Gelato does this already.

However, what mostly convinced me that we should focus on CPU for now was some demo of a raytracer written in variants both for CPU and GPU. The GPU version was only twice as fast as the CPU version running on one core and it didn't have all the effects included (e.g. shadows), on a relatively high-end graphics card. Add a second core, and the speed evens out. Make that four cores and the CPU is already twice as fast. Eight cores... you get the point.

I'm not saying that GPU raytracing will not be available one day, and NVidia certainly knows more about this than anyone else, but we have to deal with what is available now.

Best regards,
Vlado

[jreynolds]

Just asked around and confirmed that Gelato does use the CPU to raytrace ATM.

Apparently is has allot to do with the GPUs nature of working on lots of identical tasks as apposed to a CPUs ability to work on lots of different tasks at the same time.

--Jon

[^Lele^]

And while using the CPU to do that, it's also mighty slow due probably to the focus on implementing GPU algorithms, rather - like Chaos - on developing smart , efficient ways to raytrace.
Compare an AO from Gelato and one from VRay, and let me know...

This said, there are a number of clever ways around brute-force (for adaptive it is) raytracing.
Area-shadows and dynamic forms of GI (or reflections and refractions) have been shown in Crysis, and they are clever hacks, but looking mostly like the real thing.

[davidr]

Ha ha, April Fool! Vlado sure had you guys going! Realtime LC/PPT, ROTFLMAO!!! OK, but seriously, when can I get it?