I used to work at a place that had a VERY cool CMM machine, back in the late 90's.
I had a little training on it, you could basically put just about anything in it and it had a probe that would work its way around the part and measure everything down to extremely tight tolerances. We used it for quality control, to make sure the parts coming off the line were within tolerance.
Very neat tool, had a ruby tipped probe with X and Y axis arms, so it could go down 'inside' a part and measure hole diameters, etc. You just had to give it basic parameters so it would know how far to move the head before slowing down and expecting to 'hit' the part and take a measurement.
I do remember the guy who ran it missing a decimal point once - crashed the probe head into a steal bearing housing at full speed.... HARD. That was an expensive decimal point.
Jim