The returned value is a primitive number that can be used with the Set Attribute VOP to change the value of the primitive, but is not the final primitive number of the primitive.
This only works in certain VOP contexts where geometry creation is enabled. In particular, the Geometry VOP DOP, Geometry Wrangle DOP, POP VOP DOP, POP Wrangle DOP, Attrib VOP SOP, Attrib Wrangle SOP, Volume VOP SOP, Volume Wrangle SOP.
All geometry creation is done after all the elements have been processed. Therefore, you cannot read from geometry you just created.
Refers to what geometry to write to. The default of 0 means the currently processed geometry.
What sort of primitive to create.