Netfabb - Innovative software solutions for 3D printing and additive manufacturing.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Sculptris - Sculptris: Enter a world of digital art without barriers.
meshmixer - meshmixer is an experimental 3D modeling tool for making 3D mashups without too much hassle.
Misfit Model 3D - Misfit Model 3D is a 3D model editor that basically operates with triangle-based models.
FreeCAD - An open-source parametric 3D modeler