Hi Andrew, thank you for the example, but this also appears black in my scene. Lars. Bissell, Andrew wrote: > I have used this before for a lightpipe diffuser using PMAP, the figures > were just best guess coupled to a visual trial and error process. > > void trans transdisc > 0 > 0 > 7 0.8 0.8 0.8 0 0.01 0.8 0.8 >