And "without altering the shape of the mesh" you won't get anything, at least unless the model was done badly upfront with lots of unneeded geometry. (for normal maps etc you don't need real geometry, subdivision modifiers do it as well)
As I said, Dreamora. this for models generated by Maplet. CSG modellers tend to generate fairly fractured geometry (picture a quad made up of three or more polygons when it only needs two, for example).