And it's free!
By Jonathan Westhues
Maybe this can interest you ;)
http://solvespace.com/index.pl

http://solvespace.com/vids/demo.wmv

Any problem for export to Moi! (STEP) (alas inverse is not yet possible)



PS I am translating in French his site! ;)
http://solvespacefr.weebly.com/