Yes, to do that all in Bryce with no post would be mighty difficult (not impossible, but difficult). I rendered the building that the ships fly out of as one layer, then i rendered a mask, then I rendered the ships flying out, then I rendered the background city. I did that cause it makes life easier. I can control each object more, can add blur to the background but not the ships, and also because my computer couldn't hold any more than that (sad but true). All it could really take at once was either the background city, the building, or the ships. but still, all animation was done with bryce.