In Houdini I created a base geometry with packed instances (scales) copied on everyone of its points (I used a "copy to points" node with "Pack and Instance" checked). I assigned color to the scales and the base geometry later on in the stream and promoted the Cd attribute to Vertex.
I exported an .abc file with a ROP Alembic node (I checked "Use Instances when possible" and I tried both "Packed Transform: Deform Geometry" and "Packed Transform: Transform Geometry" since I have no clue of which one to use).
Once I open the file in Maya with the GPU Cache node I use the AI Use Data Color to read the Cd attribute I exported from houdini.
The base geometry render with its vertex colors as it should, but the instances render black. Why?
The GPU cache node has a Make Instance and Use Instance Cache options which I have 0 clues about what they do (nothing changes when I check them or uncheck them).
Is there a way to render the vertex color of the packed instances the same way it is possible to do it with the default not instanced geometries? Or any custom attribute really.
In Mantra I can click on "Use Packed Color" in the principal shader and that does the trick.