Instanceable Reference Crash with Cryptomatte AOV

[podorvan]

Render crashes when using an instanceable reference with Cryptomatte AOV. The crash occurs if the top-level asset prim (e.g. /ASSET) is assigned the attributes primvars:arnold:subdiv_iterations and primvars:arnold:subdiv_type.

Steps to reproduce the behavior:

1. Create a USD asset with a top-level prim (e.g. /ASSET).
2. Assign the attributes primvars:arnold:subdiv_iterations and primvars:arnold:subdiv_type to this prim.
3. Reference this asset as an instanceable reference in your scene.
4. Add a Cryptomatte AOV to the render.
5. Start the render.
6. Observe the crash.

Render should complete successfully with Cryptomatte AOV, even when the top-level asset prim has Arnold subdivision attributes and is referenced as instanceable.

• Arnold: 6.4.5.0
• USD: 0.25.5
• OS: Windows 11 Pro
• Any 3rd-party app: Houdini 21.0.512

instanceable_ref_crash.zip

[autodesk-oss-arnold-bot]

Issue synced internally to ARNOLD-17094

[cpichard]

Hi Pavel, thanks for the bug report, we'll have a look.

[sebastienblor]

Hi Pavel, FYI we're trying to fix the crash. However, arnold won't be able to render what you've been trying to do here. We cannot have different subdiv settings for instances, because then the topology changes and it's no longer an instance from the renderer point of view. So we'll either fix the crash by somehow ignoring these settings, or we'll make it so that these meshes are not instances which will give the correct result but not the optimizations you'd expect.

[podorvan]

Thanks for the update and for looking into this. Since the subdiv settings were set accidentally and not intentionally, ignoring them to fix the crash would be perfect.