Mark,
The default CMM or one that exists within Silma that has the same volumetric size (or close to it) should work pretty well. The bottom line is, if your part is larger than the size of your volume then problems will exist. I have two seats of the Silma software currently and had one for over five years that we never used. Once some time is invested it really pays off. Especially if your DMIS engine runs your controller well from pure DMIS code.

Ray Admire
Lead Quality Engineer, CMM Programming
Lockheed Martin Missiles and Fire Control - Dallas
972-603-2074