I do quite a lot of work on 3D triangle meshes, making them, deforming them, matching them, etc. etc. So I am on the lookout for a good mesh manipulation library that I can use rather than writing all the code myself.

My checklist of points I am looking for is:

• Only does mesh manipulation - I have much better libraries for writing GUIs, rendering, loading files, doing maths etc.
• Python bindings are required - write C++? Are you kidding? This is 2010!
• Active community.

And so without further delay the contestants:

gts

Seems to be just a library for mesh operations. Includes decimation, triangulation and stripping. Does not seem to have had an update since 2006.

osg

Scene graph library, has some mesh editing classes for e.g. delauny triangulation. Very active.

blender

Open Source 3D graphics programme. Has plenty of functionality for manipulating meshes and scripts exist to perform many mesh editing tasks such as decimation. However projected is targetted at user editing of mesh rather than computational manipulation of geometry. Very active.

vcg

Templated C++ library for editing triangular and tetrahedral meshes. Seems to be active. Used in the popular MeshLab application.

VTK

Visualization toolkit which has some mesh manipulation routines as part of the codebase. Used in the MayaVi. Has Python wrappers.

XGRT

Graphics "rapid prototyping" system which encompases mesh manipulation, scene graph, rendering and GUI in one environment. Seems active. C++

Currently I am going to look at vcg first. It might be that I can use SWIG to instantiate some templates and wrap the library up for python. If so, then this looks like a real winner. However if it can't be easily wrapped up, then maybe one of the other C++ libraries such as XGRT will be a contender.

Any other suggestions?