The vxf library for voxelization, described in “Alias-free Voxelization og Geometric Objects” by M. Sarmek and A. E. Kaufman, can be found under GPL at:
http://www.cs.sunysb.edu/~vislab/vxtools/
Distance to triangle code, by Geometric Tools Inc. (alias Magic Software)
http://www.geometrictools.com/LibFoundation/Distance/Distance.html