Vray GPU hybrid rendering, but what about CPU?

[seandunderdale]

Hi,

I recently upgraded my GPU, mostly for textures, viewport performance, and stability reasons. I then remembered Vray has hybrid rendering, but see that both CPU and GPU can only work using the GPU render engine. Is there any plan to allow the GPU to help out on the CPU render engine....or is this not even possible?

[vladimir_krastev]

HI, thanks for posting. In hybrid mode the rendering calculations are spread between the CPU and GPU - https://docs.chaos.com/display/VMAX/...dtheCUDAEngine

This is how you can enable it in 3ds Max

[seandunderdale]

Hi thanks for the reply. I saw that option in Maya, and understand that I can run both CPU and GPU on the GPU renderer....but is it possible, or will it ever be possible to have the GPU help out on the CPU renderer? My primary engine has always been CPU and I have a 3990x, but having swapped out my 1080ti for a 3090, I was wondering if the 3090 would ever be able to help the cpu render engine?

[oglu]

I dont think thats possible. GPU cant do a lot of stuff CPU can do.

[Muhammed_Hamed]

Like what oglu pointed the GPU hardware has limitations, it cannot run the CPU code hence we have 2 separate engines, V-Ray and V-Ray GPU. With V-Ray GPU we are limited to what the CUDA and Optix APIs could do
If you use the standard V-Ray renderer, Lens effects and denoising could be HW accelerated by GPU. That is it is about it

I recommend testing V-Ray GPU Hybrid mode on your existing scenes to see if there is a benefit. The GPU engine could be an option if you ever need it, depending on what you do of course. With V-Ray 6 this comparison will be easy to do as the GPU UI converts all your settings between the 2 engines.

Generally speaking your 3090 should be as fast as your 3990X in CUDA X86 mode, so combining both might be faster than using the standard V-Ray renderer.

Best,
Muhammed