Mesh Colours output Rhino preview not displaying alpha

Perhaps this is something basic about Grasshopper and Rhino that I don’t understand, but the Rhino preview of a mesh surface with alpha is not showing the alpha. I’d like to see my Rhino preview with alpha on certain objects.

Do I have something misconfigured in Display Options?
Also, not sure I’m approaching it right. What is the best way to show brep and mesh geometry with custom color with alpha?


Mesh vertex colors do not use alpha, it seems.

Like you can’t give alpha to colors of geometries on rhino (layers, texts, curves, etc) , alpha channel is there, but not used.
(I’m making an assumption here, i might be wrong)

Use materials instead.


If you bake the [Preview] component you’ll get a geometry with a material already applied.