the number of lights, reflection, refraction, transparency, and volumetrics are the main contenders to slowing Bryce renders. Bryce 5 sux at transparency and reflection times...especially if you intend to see something beyond the transparent areas. there are a zillion ways to reduce render times in Bryce..but almost all will reduce the quality of your picture. lights...if you have a lot of lights, this will really increase the time. You can reduce the number of lights and place a single low intensity light with "shadow casting" turned off and "infinite" turned on to get some brightness to the scene without a zillion lights. If you are using volumetric lights, worlds, or materials...you will always see a slower render..no matter what program, if its raytracing..it will be slower. materials with bump in the distance are unnecessary..even tho you can not see it, bryce is still mathematically adding bump ...you can remove/reduce this on distance objects. reflection, refraction...you pretty much are stuck with slow renders, no matter what you do if you have this. There are various premium options within the render settings that can decrease the number of times a ray bounces around before bryce assigns a color to a pixel...In some cases, this will help. grouping, tho not significant..doe indeed decrease render time... bryce "feels" for objects if it has to feel for a blade of grass, before it renders it..the calculations slow it..if however its a group of these blades of grass..then it knows there are objects in this area..and will reduce the number of calculations necessary to find the objects. This is one of the primary functions of "spacial optimization"... and of course it you are using 'soft lighting', just grin and bear it :) luck BT