Attached Link: http://www.bryceworks.com/br5stuff/tanker.html

Lot of fun, I also like the "roll your own" physics simualtion games. The only downside is a lot of the really complex primitives don't export and the files can be huge. But something like this would make a great modeler for Bryce. The link above is to a Groboto/B5 image of a single object, right out of the presets. Best-Dan