I had problems with the 3D machining before the last update as well. But that is fixed now.
Here is a link to a 3d job we just did for a customers Harley drag bike.
http://www.stripbike.com/ubb/Forum10/HTML/000052.html
I used plunge roughing on this job and then machined with a 16mm ball cutter.
Came out just like the 3D drawing........
Greig