Read and write generated coordinates (also known as "original
coordinates", "reference coordinates", or "orcos") from and to Alembic.
A custom geometry property named "Pref" is used for (hopefully)
interoperability with Maya and Houdini. For now it's only guaranteed for
Blender-to-Blender.
Export: writing generated coordinates is optional (on by default).
Import: generated coordinates are always read whenever the reading of
vertex data is enabled.
Manifest Task: T88081
f9567f6c63