I have a CAD model with a circle, nominally 7.8" in diameter. I can only measure about 90 degrees of the circle, so it's more like a radius. Using 6mm Probe. Clicked on the CAD to do an Autocircle of this 7.8" diameter O.D. radius, but for whatever reason it selected I.D. of the same diameter. Correct workplane, everything that I can see. I didn't notice that the autocircle defaulted to ID so I measured the O.D. and continued on. Now the diameter is off, as expected due to probe comp. But it is off 12mm. Can someone explain that to me? Shouldn't the error be 6mm??? Please help.
