To Create a Datum Axis
1. Click > 
Datum Axis. The Datum Axis dialog box opens.
Datum Axis. The Datum Axis dialog box opens.2. Select a primary reference in the graphics window such as a plane, surface, edge, vertex, curve, or datum point. The selected references appear in the References collector in the Datum Axis dialog box.
 | • To add more references, hold down the CTRL key and select the required referenced in the graphics window. • Select the constraint type in the adjacent to the selected reference in the References collector. • If you select a surface or a datum plane as the primary reference, you must specify two offset references. Click the Offset references collector and select the references in the graphics window. You can also drag the reference handles in the graphics window to specify the references. When you drag the reference handles, IDD highlights the valid references. |
3. To adjust the outline display of the datum axis, click Adjust outline in the Display tabbed page.
4. To adjust the size by specifying the length of the datum axis, select Size in Display tabbed page and specify the value for Length.
| | • The length of the datum axis is not displayed in the graphics window. • Handles for outline for dimensions are displayed at each corner of the datum axis preview. You can drag one of the handles to change the length of the datum axis. |
5. To adjust the length by specifying a reference, select Reference in the Display tabbed page and select a reference such as a surface, edge, or axis in the graphics window.
6. Click OK in the Datum Axis dialog box to create the datum axis. The datum axis appears in the graphics window and also appears as a separate node on the GTS Tree.