Oops, Jack already replied. Thanks Jack! One minor nit though... Jack de Valpine wrote: > Just as a side note, you have indicated that you are interested in > illuminance values, to obtain illuminance you must be sure to render > (rpict) or sample (rtrace) using the -i switch to obtain irradiance values. Actually, you use -i in rpict, but -I in rtrace, for illuminance. -RPG