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 Please see the V-Ray GPU Setup page in addition to the FAQ.

 


Frequently Asked Questions

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  • If you have multiple GPUs, you can speed up screen refresh time by removing the GPU used for monitor/viewport redraw from the devices that GPU uses for rendering.
  • If you have only one GPU on your system, you could can try reducing the value for Rays per pixel and/or Ray Rays bundle size in  in the GPU Performance Tabtab in the Render Setup dialog. If you are rendering interactively, you can try reducing the value for IPR Rays per pixel and/or IPR ray bundle size in the GPU Performance tab (note that this optimization does not apply to high-end GPUs). This breaks up the data passed to the GPU into smaller chunks so that user interface requests can be processed faster. However, this might reduce rendering speed. You can check the difference in render speed speed (GPU utilization)  in in the VFB Stats panel and thus find the optimal settings for your system.
  • The Low GPU thread priority parameter was designed to help with this issue. Turn it on in the GPU Performance Tab in the Render Setup window.

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If you use many GPUs in DR nodes you might find that the network develops a bottleneck at some point due to the GPUs producing data very fast. To increase the size of the workload chunks that are being given to the DR nodes and help reduce the communication between the client and the servers, increase the Ray bundle size and Rays per pixel parameters in the  (alternatively IPR ray bundle size and IPR Rays per pixel) parameters in the GPU Performance Tab in the Render Setup dialog. Try values like 192/32 or 256/64.

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There are global switches that turn them off. Check the Render Setup window > Settings tab > Global switches rollout (when V-Ray GPU is the renderer).

 


 


How can I check which devices on my system can be used for GPU rendering? Why my devices are not listed?

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If 3ds Max doesn't properly recognize any CUDA devices, V-Ray automatically fallbacks to using the CPU for CUDA calculations (as if the c++/cpu device was selected for CUDA rendering).

 


 


Why is the GPU rendering not many times faster than the CPU rendering?

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If you're trying to use matte materials in situations like making a shadow catcher, V-Ray GPU does not render objects with matte properties correctly unless the Elements Active checkbox is enabled under the Render Elements tab of the Render Setup window.

 


 


Why do some parameters appear greyed out and can't be used?

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