certain textures (within same shader) not rendering in CUDA or openCL GPU IPR V-Ray 3.60.3 / Maya 2018 x64

[dangerweenie]

Hello,

I've been having an issue rendering with IPR in Maya 2018.

I have a large asset (a few dozen UDIM textures) - the IPR works fine and as expected, with the exception of a few pieces of geometry not rendering RGB (alpha shows up as solid).

The asset is a bridge that is coming from Substance - there is one master shader for everything, with multiple maps going into it (standard components like diffuse, spec, etc, but also glossiness, IOR, etc).

The missing pieces of the asset render fine in CPU IRP or CPU production.

Looking in the V-Ray RT output console (using out-of-process IPR so I can view everything), I don't see any exceptions or errors.

I've tried caching / clearing caching of textures and geo between frames. I've tried setting the mipmap resolution to 512 and native both in the IPR options and also the V-Ray IPR options.

The textures are 16-bit half EXRs, though I've left the IPR texture bit depth at 8-bit as it's yet to be an issue (will be setting to 16-bit half now and see what happens).

Not sure if the 'keep textures cached between renders' option is relevant for IPR.

Would really like to be able to light interactively for this shot - any advice is greatly appreciated. I don't see any issues with the geometry itself, as it renders fine with a different shader attached.

Any advice or troubleshooting tips is greatly appreciated!

Thanks.

[Zdravko.Keremidchiev]

Cloud you please check whether the issue persists with the latest 3.x build (V-Ray 3.60.05 for Maya). If so it would be best if you could send us an example scene to support@chaosgroup.com that we could investigate. Most probably there is something not supported by the IPR. Do you use distributed rendering?

[dangerweenie]

Hi Zdravko,

Thanks for the quick reply.

The scene is gigantic and uses several references ... i was, however, able to dig up a post where it was confirmed that V-Ray RT GPU only supports UDIM coordinated up to U[8] and V[9] in V-Ray for Modo, I think.

Coincidentally, it's textures past this range that do not render when using GPU RT. CPU RT renders correctly.

I tested the scene in V-Ray Next for Maya 2019 and it rendered fine with GPU RT.

Do you think this is the same as the UDIM limitation from that post?

Thanks,

Matt

[nikolay.kusht]

I have run some test and it seems that V-Ray 3.6 with GPU was rendering textures beyond U[8] and V[9], so this might be scene specific issue. There were a lot of changes and improvements in V-Ray Next and if this issue is not present in the latest versions this is good news. If you notice any unwanted behavior related to the UDIMs in V-Ray Next, please let us know.