Shotgunlover,

I understand (?) that scanning does not handle parts of varying depths very well.

This might be where "probing/digitizing" takes over.

Whereas scanning produces a collage of images by taking photos of the part at predetermined intervals, that can be imported into CAD and modified, probing/digitizing uses a digital probe to touch the part at predetermined intervals and more accurately measures the part.

I invite the input of the CAD/CAM/CNCers out there.

A youtube search would show you both processes.