By Trimble : it's free! ;)
http://www.teklabimsight.com/
Can be used for assemble some Moi 3D models and see complex models! ;)
Reload
SketchUp (.skp)
STEP (.stp, .step)
IGES (.igs, .iges)
etc...



Not very fabulous display! :)
Here the 2 models are in the same group!