The best (in my experience) free 3D modeling program is Blender: http://blender.org It is quite functional, and can easily do the 3D Boolean operations you describe. The interface takes some time to learn, but there are good tutorials. George http://www.georgehart.com Bernie Cosell wrote:
My wife has taken a fancy to playing around with 3d objects. Things like making a cube with circles inscribed in each face and rotating it around to see what the various projections look like, or fiddling with a menger sponge [and again, rotating it around to see what it looks like], or intersecting tetrahedra...
Anyhow, I've been looking around some and I haven't had much/any luck finding a (windows) app that'll do it -- it seems that there are a lot of 2D drawing programs, and 3D modeling/animation programs (that are generally way too complicated (and generally expensive) for the sort of hacking my wife wants to do). Any of you know of an app that might do the job? Thanks!!
/Bernie\