Indirect light not working on Arnold GPU when assets are "matted"

[am_wilkins]

Hi there,

In a simple test scene with a character asset. (Arnold Standard Surface shader with maps plugged in)
Physical sky, green shader on a grid to show indirect, etc.

NB. A "Render Geometry Settings" node has been added to "matte" the ground/grid.

Without this step, the indirect light still works.

Below is just a low roughness specular shader on an eye.

Arnold CPU - Specular Indirect AOV

Simply Switching the device to:
Arnold GPU - Specular Indirect AOV

All the indirect information is gone. Also, occurs with Diffuse Indirect.

Anyone else run into the issue? Seems like quite a big one.

--

Houdini Core Version 20.0.590
Arnold Core: 7.2.5.2

HotA: 6.2.5.2

CPU: AMD Ryzen TR 3990x

RAM: 128GB
GPU: NVIDIA RTX A4000
OS: Windows

[am_wilkins]

Hi again,

Attached is a scene that the Arnold team can hopefully use to reproduce this issue.

It's a complete deal-breaker for the Arnold GPU unfortunately.

Let me know how it goes?

Arnold CPU

Arnold GPU - No indirect.

all the best,

amwilkins

[Stephen.Blair · Accepted solution]

Thanks for the scene. This is already logged as

ARNOLD-13885
Arnold GPU does not match CPU for polymesh.matte

Between CPU, GPU, the matte shader, and the polymesh.matte parameter, it's CPU and the matte parameter that is the one that is different.