CGAL mesh simplification procedures

[timpx]

Look for replacement of remesher with the more widely used and test CGAL library, while trying to keep track of the region mapping directly (#46) (which assumes avoiding complete remeshing of the surface as we are doing now)

Maybe using this, however I believe this is what is used in iso2mesh, which was not good too keep the depth of the sulci while downsampling the surface.

[maedoc]

They have a module specifically for mesh simplification

http://doc.cgal.org/latest/Surface_mesh_simplification/