Hi, Light thru transparency can be really painfull to compute sometimes. If u try to use that feature with many CS3 trees, when you'll be stuck for hours to render them :-( BTW Did u check if the "no light when fully transparent" was check on your hair texture ? This might speed up the render ? Anyhow, using bump really slow down also the render...and that's probably reasons like that that made Eovia introduce the network rendering capability with CS4 pro... Anyway that's just my 2 cents ... :-) Pete