Blender - Blender is the open source, cross platform suite of tools for 3D creation.
ArchiCAD - ArchiCAD 16 enables BIM modeling with a new green approach to planning. Create anything you need with ArchiCAD's flexible new features for design.
FreeCAD - An open-source parametric 3D modeler
ARCHLine.XP - BIM / CAD Software for 3D Architectural and Interior Design
meshmixer - meshmixer is an experimental 3D modeling tool for making 3D mashups without too much hassle.
Onshape - Onshape is the first full-cloud 3D CAD system. It runs in a web browser and on any mobile device.