Support assigning maya look to multiple separate assets inside an Arnold aiStandin with alembic files.

[BigRoy]

Changelog Description

1. Do not force remove assignments on aiStandin look assignments, but allow updating/adding assingments so that assigning looks of multiple assets inside one aiStandin shape is supported.

2. This also fixes a bug where cbId attribute exported from Houdini was not detected correctly and its value was incorrectly interpreted from the alembic property.

• Maya seems to export as alembic.Abc.IArrayProperty
• Houdini seems to export as alembic.Abc.IScalarProperty

3. You can now also list assets and assign look to gpuCache if mtoa (Arnold) renderer is loaded and is set as the current renderer.

4. This also fixes a bug where ALL assets inside an aiStandin are assigned even if only one of them was picked from the asset list in the look assigner.

We now support both.

Additional info

Fixes #160

Testing notes:

1. Create a pointcache containing geometry from multiple folders (assets)
2. Load the Alembic pointcache via AYON to aiStandin.
3. Assign the look.

It should detect the multiple assets inside the aiStandin and allow assigning each of them without applying only the last asset.

[moonyuet]

Tested successfully in Maya:

[LiborBatek]

I have used 3 different assets for pointcache and loaded it as a standin and using Look assigner correctly resulting into all looks applied to each entity inside! Really cool!

LGTM

And after using assign look: