I'm looking for a (preferably free) physics editor for Mac - something I can use to build representations of physics objects and easily get them out of it and into my Bullet-powered testbed. Ease of use is a must, as I'm a programmer and don't want to waste 30+ hours learning another app's UI. Something with support for writing exporters in a rapid-iteration-friendly language like Python would be great. Ideas?

I have been told Blender has bullet export... but I also would like to get some info on how it is supposed to work as I haven't got it.