Hello, I’m encountering an issue where I get anistropy artifacts rendering in GPU when choosing Map channel instead of Local axis. The object is unwrapped and has a UV map channel that have the anistropic metal material applied to it. If I switch VRay to CPU from GPU and render the artifacts are no longer present in CPU. If I then switch back to GPU the artifacts will go away when rendering in GPU. Eventually something will make the anistropy render with the artifacts again. It seems adjusting the material or further UV adjustments make the artifacts come back but I cannot reproduce it fully. Is there any log of this somewhere for a fix?
3ds max 2025.3.6
VRay 7.20.08 build 00000, nVidia drivers 595.97, dual RTX 6000 Ada
Attached images show GPU render with artifacts, CPU render correct and then GPU render correct after switching back from CPU.
Thanks,
Mind if you send the scene so we can troubleshoot?
Looks like a V-Ray GPU bug/cache issue in anisotropy UV tangent derivation
Scene sent. Seeing if any fixes have been found?
Sorry for the late reply. Scene received. Will investigate today.
The only way I can reproduce it is to apply the particular shader during IPR. When restarting IPR, however, everything renders correctly. Is this the case on your end?
I am not quite sure if it only happens after applying it once IPR has started or not. I know it can occur after editing the materials when IPR is started so it may be the same situation.
But does it get resolved after restarting IPR? And are there problems when rendering production?
I have not been able to test these variables. I’ll try to see if I can fit them in during project deadlines.
Some further tests reveal that I can reproduce the artifacts appearing during IPR after applying the material with anistropy to either the same object or any other object. The artifacts disappear when production rendering.
Do you, by any chance, have the CPU device enabled for CUDA rendering? If yes, does it happen if you disable it (and use only the GPUs)?
The CPU shows as a Rendering and Denoising available device but I do not have either of those checkbox enabled.
Mind if you try the latest nightly build? It seems to be fixed there.
Sure, I will try the nightly build with my 3ds max 2025 and test. Thanks!
Testing appears to have fixed the issue. Is my ability to access cosmos assets related to the nightly build? I only see assets that I’ve downloaded and it cannot connect to the service. I can roll back for now.
Great -at least we know the particular issue is fixed. Otherwise, I doubt the nightly is connected to Chaos Cosmos here is some way. Perhaps, you just had to restart the Chaos Cosmos Browser service.
