Fartuess's material structure means he doesn't have to keep going back and forth between programs to make minor changes (something that drives me nuts) which makes sense to me
brechtos is right about the structure shape, I think, the best ref pic I could find was in the rf2 cams ripped by Paul and Xav, and theres a rough model of the basic shape
http://oddworldlibrary.net/archives/togg/SS2/AO/