open3mod - A free, Open-Source 3D Viewer designed to make it all easier. Massive 3D Format support
BioBlender - BioBlender is a software package built on the open-source 3D modeling software ...
MeshLab - System for processing and editing 3D triangular meshes, provides a set of tools for editing...
pymol - PyMOL is a powerful and comprehensive molecular visualization product for rendering and animating...
noesis - Rich Whitehouse's project web site.
Online 3D Model Converter - free online 3D model converter, upload a model and export it into popular formats