I want to mix between two displacements on a volume primitive according to the density. I can't figure out how to do this in a VEX displacement shader. I am starting to think this is impossible as volume properties exist only as primitives. Anyone have a clue as to how such a thing might be done?

Also, the Volume Ramp…. I can't get the volume Ramp VOP to do what I would expect it to do. I have red at one end of my ramp and blue at the other, but the whole volume renders red… I would have thought that it would be red at the edges and blue in the center, (or vice versa). How is this thing supposed to be used?

Also, when I apply a volume ramp VOP and enable colour, my shaded view turns 100% black and comprises the bounding box of the volume only.