Aye, it's a combination of things, but I'm saying that you CAN get a handle on the situation. Both things stated were true, but one thing was wrong... So, you're running into a boolean problem? Do you still have your model, itself? Did you save it to your library? Booleans can become really complex in Bryce, because they aren't true booleans, but you can still re-group them with a little effort and a lot of patience. Just lock down everything but the top piece (where the errors are), maybe even set everything else to "Show as Box", to cut down on the clutter, and re-group that piece together? As for your render itself, I think that a major part of it might be lighting. Are you using any lights other than the sun? Radials or Spot lights? Bryce 5, anyway, has this ridiculous bug where if you insert a gel into a light, ALL lights become gel lights when you re-load the scene. This could be responsible for why everything looks so dramatically different. If you are using lights other than or as well as the sun, the fix for this bug is to make sure all of your lights ARE gels before you save it. Merely set the lights that aren't SUPPOSED to have gels with a blank white material in the Material Lab. Piece of cake. I'm dying to see this one finished, so don't give up! If it gets too frustrating, merely put it away for a while and come back to it... But I dont' think 2,000 cubes are the issue. You could use ten times that number and you'd be fine, as long as you had enough RAM. Good luck, hope it works out!