Meshlab - open source

[rafpug]

MeshLab
is an open source, portable, and extensible system for the processing and editing of unstructured 3D triangular meshes (Mesh Optimization).
http://meshlab.sourceforge.net/

[lacilaci]

I found it very useful in past for decimating very heavy scans that zbrush couldn't open. But nowadays even zbrush can load I guess up to 80m poly per subtool. If you are working with heavy meshes/scans you are going to need zbrush anyways for fixing and tweaks and retopo.