### (Simple) ClearanceCube Definition

When you access the ClearanceCube Definition dialog box from the Edit | Preferences | Set ClearanceCube... menu or by clicking the Clearance Cube Definition button from the ClearanceCube toolbar, it opens in this simplified interface:

ClearanceCube Definition dialog box

This dialog box contains these options:

1. - Offset value - This value determines the distance away from the CAD model on all six sides where PC-DMIS will draw the ClearanceCube. It is saved in the current part program. 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 part program. So, a value of 1 could be either 1 mm or 1 inch, depending on what was initially selected when the part program 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 will show "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. Simply type a new value if you want them the offset distances on all faces to be the same.

1. - Activate ClearanceCube motion - This check box determines whether or not the part program uses the ClearanceCube for it's motion. While ClearanceCube motion is enabled, clearance planes are disabled, and new features added to the part program will 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 will need to manually turn ON their ClearanceCube property. Clicking the Activate ClearanceCube motion icon on the ClearanceCube toolbar also activates or deactivates the ClearanceCube motion.

Motion Order

When active, motion is done in the following order:

1. 1. 1. 1. Any motion from the “After” feature measurement avoidance move selection inside the feature measurement command.

         2. Any move or motion commands that are in the part program and between the just measured feature and the next feature measurement command, or the last command, if this was the last feature measurement command in the part program. 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 will use the ClearanceCube capability to travel to the nearest available face and then traverse 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 to 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 part program. They are computed each time at execution. Each feature is assigned an initial ClearanceCube face. If there are no programmed moves 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 “Before” feature measurement avoidance move selection inside the next feature measurement command.

Warning: If Activate ClearanceCube motion is enabled, all clearance plane functionality for your part program will be disabled. ClearanceCube motion and clearance planes cannot coexist in the same part program. Be sure to check for collisions before executing your program. See the "Detecting Collisions" chapter.

1. - Show ClearanceCube - This check box determines whether or not the ClearanceCube is drawn in the Graphics Displays window. Clicking the Show ClearanceCube icon on the ClearanceCube toolbar also shows and hides the ClearanceCube. 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 per axis that way. A reddish highlight indicates the face to drag. Clicking the Resize ClearanceCube icon on the ClearanceCube toolbar also puts the ClearanceCube in resize mode. This option is only available when the Show ClearanceCube option is enabled.

   Note: The Activate, Show and Resize options described above can also be toggled from the Operation | Graphics Display Window | ClearanceCube submenu.

   - Advanced - This button expands the simple dialog box into a multi-tabbed dialog box so 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. Clicking Simple displays the simple-style dialog box.