I have a favorite vendor who only uses Mastercam when modeling parts for me. When I need a model he will convert his mastercam file into a solidworks part file but it isn't a solid model and imports as  one imported surface. I know nothing about Solidworks other than viewing models and simple sketches. I have a std version 13 and would like to learn how to convert these models into solids so I can see all the geometry used to create the model and or convert it into something I'm used to seeing. If any of this makes sense to you please respond in layman terms so I can understand.

                                                                                     Dave