I don't know exactly, but you mentioned cutting out MDF board.
why not export a dxf and import the dxf in your cnc cad program ?
Or maybe if the building is solid, use the ruby slicer, so you've got
the building in thin piece's and export these with ADO ? and import these in the cnc-programming software.
what kind of cnc-machine are you talking about (how many axes ?)