Creating a Datum and Datum Targets

This task shows you how to create a datum and datum targets on body in white surfaces.
Open the Tolerancing_Annotations_06.CATPart document:

  1. Right-click the Datum scheme capture and select Set Current from the contextual menu:
    all created annotations will be added to this capture as long as it is current.

  2. Click the Tolerancing Advisor  in Annotations toolbar.

    The Semantic Tolerancing Advisor dialog box appears.

  3. Select the four surfaces as shown on the part. The last selected surface will support the datum.

     
    The Semantic Tolerancing Advisor dialog box is updated.
    The buttons and options available in the dialog box depend on your selection.
     
     

    The Propagation Selection options are displayed according to the type of face selected depending on the canonicity. In this scenario the options are not used. For more information, refer to Propagating Geometry Selection for Feature Creation.

  4. Click Semantic Datum (N surfaces):

    The datum is created.
    The Datum Definition dialog box appears.

  1. Click Add in the Datum Definition dialog box.

    The Datum Target dialog box appears. Keep the options as is.

  2. Select the target points as shown on the part.
You can select the geometry (which should be inside the geometry referenced by the datum feature).
  • If selected geometry is a point or vertex, the three options are available to specify the form (point, circle, rectangle) and the size of the limited zone.
  • If the selected geometry is a curve or a surface, the three options are disabled. This is because the selected curve or surface itself defines the form and size of the limited zone.
You do not have to click OK in the Datum Target dialog box, selecting another point automatically validates the datum target creation.
 
 
 

  1. Click OK in the last Datum Target dialog box to end the datum target creation.

    The Datum Definition dialog box is updated.
 

  1. Click OK in the Datum Definition dialog box.

    The datum and datum targets are created in the geometry and specification tree.
     
 

  1. Do not close the Semantic Tolerancing Advisor dialog box to perform the next task.