#### Point Target Radius

The Point Target Radius box allows you to specify the target radius tolerance for measured point features used as inputs in the alignment. Measured input points include the following:

- MEAS/POINT

- AUTO/VECTOR

- AUTO/EDGE

- AUTO/SURFACE

- AUTO/ANGLE

While you can easily see the location needed to measure a circle on a part, determining the exact location to measure a point on the surface isn't easily done. Without any visual indicators telling you where to measure the point, it is difficult to manually measure the point in an exact spot. The Point Target Radius allows you to specify an imaginary tolerance zone (or target) the size of the radius, around each point. This allows you to touch anywhere within the indicated tolerance. If the measured point did not touch within this zone, PC-DMIS will re-measure the point in DCC mode.

PC-DMIS will attempt to re-measure the input features based on the selected check boxes in the Iterative Alignment dialog box (See "Meas All Once" and "Meas All Always").

If you don’t select the Meas All Always or Meas All Once check box (or if you manually set MEASURE ALL FEAT=NO in the Edit window),

- PC-DMIS will fit the datums and check to see if any measured input points missed their targets. If so, only these features will be re-measured in DCC mode.

- PC-DMIS will display a dialog box indicating the feature that is about to be measured. This will let you ensure that the probe can reach the desired feature without colliding with the part.

- Once all point features are in target, PC-DMIS considers the iterative alignment command complete.

- If there are any measured point features that missed their targets, PC-DMIS will continue to re-measure these features until they are in target.

Note: It is important not to set the vector Point Target Radius value too small (for example 50 microns ). Many CMMs are unable to accurately position the probe to touch each measured point on a minuscule target. A better choice would be a tolerance of about .5 millimeters. If the re-measurement continues indefinitely, you should increase this value.