Primvar
The name primvar comes from RenderMan, and stands for “primitive variable”. A primvar is a special attribute that a renderer associates with a geometric primitive, and can vary (interpolate) the value of the attribute over the surface/volume of the primitive. In USD, you create and retrieve primvars using the UsdGeomImageable schema, and interact with the special primvar encoding using the UsdGeomPrimvar schema.
API
VEX