can someone explain why this Shader renders wrong on GPU?

[skx555]

Rubber Material renders probably on CPU with Arnold 5.4.0.0 C4DtoA 2.6.0

same Rubber Material with GPU Arnold 5.4.0.0 C4DtoA 2.6.0

Node

arnold-shader-network-editor.jpg


Scene Files

c4dtoa-gpu-rubber-material-test-scene.zip
hdr.zip

[DeclanRussell]

I'm not seeing anything that sticks out in the shading network. Could you export this to an .ass file for me please? I don't have C4D to hand.

[RGhost77]

ramp_rgb Connected colors and positions not supported.

https://docs.arnoldrenderer.com/display/A5ARP/Supported+Features+and+Known+Limitations

I think that's why ...

[skx555]

Thanks for having a look.

FYI
Windows 10
GeForce RTX2070
NVIDIA Studio Drivers 431.70
Optix 6.0

rubber-material.ass

[skx555]

Yeah I guess, well, I have no idea how that one flew over my head.

[adrien.herubel · Accepted solution]

Hi, we found the issue there is a bug in how the tscale parameter is handled on the image node. This is tracked internally in #8758, and should be fixed in an upcoming bugfix release.