Cleanup and namespace map editor stuff under Tools.MapEditor, MapDoc class -> MapDocument SimplePolygonMeshDescription (mouthful) defines a set of n-gon polygons that can be turned into a half edge Hammer mesh. Explicitly this is simple because vertices are repeated, this isn't performant but it's 1000x easier to do simple things, I'll probably add an additional advanced API for nerds. This will merge coincident vertices on the Hammer mesh if set and within a tolerance.