Maya USD: Custom attributes: What is supported?

[paulgolter]

Hello everyone,

I would like to get a clear picture what the maya-usd plugin currently supports regarding importing / exporting custrom attibutes.

I am also not a maya expert so I might not have all the knowledge concerning maya attributes in general.

In USD we can have attributes with:

1. Interpolation Type

• Constant – per object (one value for the whole geometry)
• Uniform – per face / polygon (one value for all vertices in that face)
• Face variying – per face-corner (shared point can have a different value in each face)
• Vertex – per point / vertex (shared point has only one value across all faces it’s part of)

2. Data type

• Too long to list here (bool, int, float, vectors, strings, etc [...])

3. Time Sampling

• Static
• Animated

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Some things I believe I found out that are supported:

Import:

• Constant attributes are imported as maya custom attribute but animation is not supported?
• Uniform / vertex / face varying attributes are imported as maya color sets, but no animation supported?

Export:

• Maya custom attributes can be exported by specifying a custom attribute (USD_UserExportedAttributesJson) on an object following this format that defines what maya attributes should be exported to usd

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My question: From the above options what does maya-usd support / and what are the limiations when importing (as maya data) / exporting (from maya data) usd files?