MESH Optimization_HEXAGONS AND SINGULARITIES

What I want to do is optimize the mesh I have, which is composed by various tipes of polygons. From this mesh I want to obtain one based in hexagonal polygons, with singularities of pentagons and heptagons, and deciding how many singularities to leave on the mesh. To do this I was trying to find the central vertices of the polygons, identifying those that are 6-sided or different. But it would be great just having an hexagonal mesh with singularities of pentagons and heptagons....

ANY IDEA??