Basically adds more 'boxes' to every polygon so the end result is really packed. Its main use was for distant City shots i think (ground planes etc..) but i saw someone use it in a totally different way and i really got hooked on it its an awesome tool.
Thanks but what most people look past is the actual material of the objects.
I used Final Render Stage 1 as far as i can recall. The material was a highly reflective material and i also used another plug-in for volumetric purposes such as an omni light that shoots rays of 'volumetric dust'. Other than the overall composition took a bit of time as i didn't quite know how many reflections would come up during the render.