anyone can tell me where I can find a mathematical demostration of this shadow matrix? P = normalize(Plane); L = Light; d = dot(P, L) [ P.a * L.x + d | P.a * L.y | P.a * L.z | P.a * L.w ] [ P.b * L.x | P.b * L.y + d | P.b * L.z | P.b * L.w ] [ P.c * L.x | P.c * L.y | P.c * L.z + d | P.c * L.w ] [ P.d * L.x | P.d * L.y | P.d * L.z | P.d * L.w + d ] thanks [edited by - q2guy on March 6, 2003 6:00:04 PM]