Tolerance profile of a point

For the example above and all others in this document, the nominal surface is shown in red and the actual surface is shown in green.    

1) The Point and nominal vector is defined.

2) The point is measured.

3) Probe compensation is calculated along the nominal vector.  Note in the illustration above we can see even when the drive vector is not prefect the probe compensation is still calculated along the nominal vector.

4) The compensated point is projected to the nominal vector (projection is shown in blue).

5) The deviation is calculated along the nominal vector.

6) The tolerance report shows deviation along the nominal vector.

In short, a point is a point.  While the illustration above shows a point on a curve, it is important to remember that point evaluation views each point individually and does not relate the information to the curve.  

Tolerance profile of a point reports ONLY the deviation along the nominal vector.  Hence, machine placement errors are not visible to the user.