PowerSHAPE direct support for Rhino 3DM files: http://www.powershape-e.com/general/cad_data.asp
PowerSHAPE is a NURBS-based hybrid surface and solid modeler. It also has the ability to combine triangulated artwork, wrapped onto and trimmed into the model. Delcam calls this Total modeling.
A completely free version of PowerSHAPE (containing the full modeling functionality) is available: PowerSHAPE-e.