(Simple) ClearanceCube Definition

To open the ClearanceCube Definition dialog box, from the Edit | Preferences | Set ClearanceCube... menu or from the ClearanceCube toolbar, click the Clearance Cube Definition button .

ClearanceCube Definition dialog box

This dialog box contains these options:

• Offset value - Determines the distance away from the CAD model on all six sides where PC-DMIS draws the ClearanceCube. It is saved in the current measurement routine. The cyan-colored rectangle indicates the surface that PC-DMIS assumes the part is resting on. PC-DMIS uses the same units of measurement as the measurement routine. So, a value of 1 could be either 1 mm or 1 inch, depending on what was initially selected when the measurement routine was created. Increasing the offset value increases the size of the ClearanceCube. If the offset distance is not the same for all faces, this box shows "N/A". This can happen if you modified the offset distance for specific faces in the Advanced dialog box and then came back to the Simple dialog box. Type a new value if you want the offset distances on all faces to be the same.

• Activate ClearanceCube motion - Determines whether or not the measurement routine uses the ClearanceCube for its motion. While ClearanceCube motion is enabled, clearance planes are disabled, and new features added to the measurement routine have their ClearanceCube property on the Status tab of the advanced-style ClearanceCube Definition dialog box set to ON. If you want existing features to use ClearanceCube motion, you need to manually turn ON their ClearanceCube property. You can also turn the motion on or off from the ClearanceCube toolbar, by clicking the Activate ClearanceCube motion icon .

Motion Order

When active, motion is done in the following order:

1. Any motion from the feature measurement used with the AFTER option in an AVOIDANCE/MOVE command within an Auto Feature command.

2. Any move or motion commands that are in the measurement routine and between the most-recently measured feature and the next feature measurement command, or the last command, if this was the last feature measurement command in the measurement routine. This includes any tip change commands, which are handled as a special case.

   How Tip Change Motion is Handled

   When ClearanceCube motion is activated and you inserts a tip change command, the change in tips requires a probe rotation. PC-DMIS follows the probe tip vector out to the face it used to enter the cube. It then traverses the part until it reaches one of the edges of the face that is the closest to where the probe is when in its retracted position. A distance value is then calculated as the distance from the center of the probe head to the end of the styli. The offset value is 110% of this distance. The next move is away from the part by this offset value followed by the probe rotation. The next move is back to the ClearanceCube boundary.

3. Any motion to the ClearanceCube and around the ClearanceCube to get the probe to a position where there is a clear path to the next feature to be measured. These are the planned motions from this enhancement. Note that these commands are computed and executed, but not added to the measurement routine. They are computed each time at execution. Each feature is assigned an initial ClearanceCube face. If there are no move commands and if Activate ClearanceCube motion is enabled, this is the face for the initial move from this feature to the ClearanceCube.

4. Any motion from the feature measurement used with the BEFORE option in an AVOIDANCE/MOVE command inside the next Auto feature command.

If Activate ClearanceCube motion is enabled, all clearance plane functionality for your measurement routine are disabled. ClearanceCube motion and clearance planes cannot coexist in the same measurement routine. Be sure to check for collisions before executing your measurement routine. See the "Detecting Collisions" chapter.

• Show ClearanceCube - This check box determines whether or not the ClearanceCube is drawn in the Graphic Display window. You can also do this from the ClearanceCube toolbar by clicking the Show ClearanceCube icon . If this option is enabled, it also enables the Resize ClearanceCube option described below.

• Resize ClearanceCube - This check box places the ClearanceCube in resize mode. When in resize mode and the ClearanceCube is visible, you can click and drag a face of the ClearanceCube and set offset distances for an axis that way. A reddish highlight indicates the face to drag. You can also do this from the ClearanceCube toolbar by clicking the Resize ClearanceCube icon . This option is only available when the Show ClearanceCube option is enabled.

You can also use the Operation | Graphic Display Window | ClearanceCube submenu to toggle the Activate, Show, and Resize options described above.

• Advanced - This button expands the simple dialog box into a multi-tabbed dialog box so that you can set more specific options. The tabs on the advanced dialog box include: Size, Constraints, and Status. This button then changes to read Simple. You can click Simple to display the simple-style dialog box.