If I have four variables that store the points of a quad, how can I calculate and use the face and vertex normals? Thanks! -David

http://nate.scuzzy.net/normals/normals.html Talks about normals and vertex normals.

u only need ANY 3 points from the 4 points to calculate the normal. to get the vertex normals 4 smoother shading u also need the faces that surrond that polygon

http://members.xoom.com/myBollux

Take three points on the plane and
P1P2 X P1P3 to calculate the normal