By default, PC-DMIS matches the measured points in your best fit alignment to the original nominal point set. However, by enabling Iterate and Repierce CAD (see the Iterate and Repierce CAD area discussed in "Description of the Best Fit Alignment Dialog Box"), you can have the best fit alignment match the measured points to CAD curves or surfaces instead. In this case, after the first best fit alignment is computed, updated nominal points on the CAD curve or surface, corresponding to the transformed measured points, are calculated. This process is repeated until convergence takes place. This alignment method changes the theoretical values of the points.
If the re-pierce operation fails for all of the measured points included in the Best Fit alignment, PC-DMIS will display an error message in the Warnings area and abort the alignment calculation.