The Retract Distance box lets you enter the distance the probe retracts from the surface after taking a hit. If necessary, PC-DMIS can automatically change this value when it takes hits on an arc or circle.
The Edit window command line for this option reads:
RETRACT/nnn.nnnn
Where nnn.nnnn is a number value for the distance.
Some controllers do not retract on their own. In these cases, PC-DMIS issues the move to do the retract, and the distance is based on ball surface to the part's theoretical hit location. If the controller does do the retract, the distance may be calculated either from the ball surface or the ball center to either the theoretical or measured hit location, depending on the particular controller.