Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Vectorworks - Vectorworks 2D / 3D CAD and BIM software for Mac or Windows provides one flexible solution for your entire design process. Sketch, model, and present with the ultimate software from start to finish.
FreeCAD - An open-source parametric 3D modeler
VARKON - Varkon is a very powerful parametric 2D/3D CAD, modeling and application development tool for...
meshmixer - meshmixer is an experimental 3D modeling tool for making 3D mashups without too much hassle.
ArCADia-Architecture - ArCADia-Architecture is a revolutionary component for the instant creation of architectural documentation and object drawing.