A face that is painted on both sides. Effectively the 3D renderer skips the orientation check and paints the face in all cases.
Face > DoubleSidedFace
Calculates the average z-value for the face based on the supplied world points (which may have been transformed).
Calculates the normal for this face based on the supplied world points (which may have been transformed).
int getVertexIndex(int i) #
Returns the index (including offset) for the specified vertex.