Blender - Blender is the open source, cross platform suite of tools for 3D creation.
GoodBarber - GoodBarber is a mobile app creation platform.
FreeCAD - An open-source parametric 3D modeler
Fuse - Fuse is a UX tool suite for mobile app designers and developers.
Sculptris - Sculptris: Enter a world of digital art without barriers.
Dropsource - Mobile development platform for building native iOS & Android apps