It is done by using layers - about 25 I think. Each layer taken using the same terrain (i.e. castle, smoke, ground), same point of view, but with a different part of the population in each. Total size of all the bryce files used for the layers is about 4.3GB. Approx 2400 attackers, and maybe 200 defenders in scene. Started it in late october, but had a few distractions along the way.

Dreams are just nightmares on prozac...
Digital WasteLanD