prism - create a closed right prism


prism v1 v2 ... vN length


Create a closed right prism using the current material. One end face will be enclosed by the named vertices, and the opposite end face will be a mirror image at a distance length from the original. The edges will be extruded into N quadrilaterals connecting the two end faces.

The order of vertices determines the original face orientation according to the right-hand rule as explained for the f entity. Normally, the prism is extruded in the direction opposite to the original surface normal, resulting in faces that all point outward. If the specified length is negative, the prism will be extruded above the original face and all surface normals will point inward.

If the vertices have associated normals, they are applied to the side faces only, and should generally point in the appropriate direction (i.e. in or out depending on whether length is negative or positive).


# Make a unit cube starting at the origin and \
	extending to the positive octant
v cv0 =
	p 0 0 0
v cv1 =
	p 0 1 0
v cv2 =
	p 1 1 0
v cv3 =
	p 1 0 0
# Right hand rule has original face looking in -Z direction
prism cv0 cv1 cv2 cv3 1


cyl, cone, f, m, ring, sph, torus, v