Rhinoceros 3D CAD is a NURBS modeler . Not every CAM software supports
all the NURBS features that Rhino has. Therefor you have to convert the
NURBS surfaces into a mesh format the CAM software can read.
When you convert the NURBS to polygon meshes you should make sure that
the result has a reasonable count of mesh faces representing all the details
It might be a good idea to measure the parts and print out a rough drafting
sketch to have a reference when you are drilling holes manually.