tet_faceindex

int  tet_faceindex(int faceno, int vtxno)

Returns -1 if an invalid number is specified.

Returns 0 to 3 to refer to the four vertices of a generic tetrahedron.

faceno

The face on the tetrahedron. Face 0 is the triangle that doesn’t have vertex 0.

vtxno

Which vertex on the triangle to return, 0 to 2. Starts with the lowest number and follows Houdini’s winding convention, ie, face 0 is vertices 1, 2, and 3.