To probe hem-edge points with a spherical probe

For each hem-edge point measurement you want to make, you must probe two points:

• The first point must be located on the nearest surface of the CAD model. This sets the nominal plane and direction used to calculate the position of the hem edge point.
• The second point must be located on the edge itself. It is projected onto the nominal plane to determine the actual position of the hem edge .

The total deviation from the nominal position is calculated from the two partial deviations.