V-Ray RT GPU rendering on a Render Farm

[intervoke]

We have a render farm with 12 Alienware Area 51 computers using 3dsmax, Maya and Softimage and after doing some research on GPU rendering there are some amazing performance gains that can be achieved over CPU rendering. Is there away to use this technology on a render farm, by just pushing render to farm? Is there any difference with the images rendered on a GPU opposed to CPU? I noticed there are a few render farm services online that use this feature and I want to know more about it.

Does anyone have any insight on this technology? Any advice would be greatly appreciated!

Thanks in advance!

[vlado]

There are differences in the features supported on the GPU vs CPU, so you must be a bit careful about what features are used in the scene. You can find a more detailed list here:
http://docs.chaosgroup.com/display/V...orted+Features

By "render farm" do you mean an online render farm service or a local render farm in your office?

Best regards,
Vlado

[intervoke]

By Render farm I mean a local render farm in our office. Do people use the GPU rendering as a replacement for CPU rendering?

[vlado]

By Render farm I mean a local render farm in our office. Do people use the GPU rendering as a replacement for CPU rendering?

Some do, yes. Based on what I've heard, the preferred approach is to put several GPUs in a few of the machines, making them very fast render boxes, rather than setting up each farm machine with a GPU of its own.

Best regards,
Vlado

[Alan Iglesias]

...Do people use the GPU rendering as a replacement for CPU rendering?

Yes, some of us do. As Vlado said, if RT/GPU rendering is adequate for your rendering requirements, go ahead and put together machines that can handle multiple GPUs. There are plenty of motherboards out there that can easily handle up to four GPU cards. This will give you the best "bang for the buck", GPU rendering-wise.

Best of luck,

-Alan

[particlerealities]

I'm a complete novice with GPU because I've only recently gotten a decent GPU card to start playing with it. What I would add is this - if you think you might use GPU for rendering, then use it from the very beginning of the project (which I'm sure you'd do anyway) so you can make sure your renderings are coming out the way you expect. If you run into a hurdle with a feature that isn't supported, you can immediately find a way around it that will work with the GPU. I've opened up some old projects (prior to the latest release) and found they didn't render anywhere close to the CPU version, mostly because I used unsupported (invisible) lights. I believe they now support invisible lights so the renders are much closer to my old CPU renderings.

[ricoholmes]

I second the fact that the scene needs to be original and specific to GPU rendering. Expecting old scenes built for CPU to work on the GPU will likely lead to problems.
Particlerealities has worded it perfectly.

Having said that- if you build the scene with GPU rendering in mind, the results are outstanding, and blazingly fast in comparision. We use a GPU renderfarm (though only one GPU per box-it was the cheapest way for us to upgrade our existing farm) and i can honestly say I dont believe we'd have managed our latest project on time without it. I'm still amazed GPU is handling things so well

There are still things the GPU misses that CPU users take for granted, but Chaos Group are narrowing that gap constantly. Its worth investing in now, to be familiar with all the caveats.

[beenyweenies]

Just to add to this discussion, the entire scene must fit in the RAM of each individual graphics card, or no dice. Thankfully 6GB and 8GB cards are becoming more common and prices are coming down.

I recently tested a scene with a complex RealFlow animation (BR/BR, area lights, HDR Dome, GI etc), and couldn't believe the results. I thought it was a mistake at first. each frame went from 1.5 hours on CPU to 3.5 MINUTES on a single GPU (GTX 980ti, about $675).