CloudCompare - CloudCompare is a 3D point cloud (and triangular mesh) processing software.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Autodesk ReCap - View, Segment, register and convert point cloud data from laser scans
FreeCAD - An open-source parametric 3D modeler
Regard3D - Regard3D is a free, multiplatform, open-source structure-from-motion application.
meshmixer - meshmixer is an experimental 3D modeling tool for making 3D mashups without too much hassle.