Rhino is a super program for generating 3D models. There are things it does well and things it does poorly. I use it in conjuction with RhinoCAM to generate toolpaths. It is powerful and easy to use. When using it to make models to share with other CAD systems, it is not great. As the models get more complex, they get leaky rather than be closed solids, it is painful to fix leaky solids, there is no nice way to do this, and leaky solids won't import into fussy CAD programs (SolidWorks).