Craig- How does your manual CMM apply comp vectors to the probe center coordinates to arrive at the ball surface contact position? Or to put it another way, does the odd surface you're getting look like it may be constructed from a bunch of points that are half a ball off? I think CATIA can still offset the CAD surface by a ball radius. See if that picks up your points.

Mike Matusky
mfmatusky@aol.com