Form GCD
Forms are identified by geometry extraction as collections of surfaces that can be created with a single operation such as drawing, crash forming, pad and wipe, or bending.
Geometry extraction also classifies each form as either a CURVED_BEND or EMBOSS. The classification is reflected in the SubType property listed in the Geometric Cost Drivers pane.
Creating and Editing Forms
You can override the extracted surface groupings by using the Form Definition dialog, provided you are connected to your part’s CAD model.
To edit an existing form:
6 Right click on the form in the Geometric Cost Drivers pane and select Edit Form Definition:
The Form Editor appears:
7 Select surfaces in the Viewer or in the dialog, and use the arrows, 
and 
, to move them between the Available column and Surfaces in Form column. Note that when you select a surface, the opposite surface (directly on the other side of the blank) is automatically selected. Pairs of opposite surfaces are listed in the Geometric Cost Drivers pane under the Parallel relation, under GCD Relations.
and , to move them between the Available column and Surfaces in Form column. Note that when you select a surface, the opposite surface (directly on the other side of the blank) is automatically selected. Pairs of opposite surfaces are listed in the Geometric Cost Drivers pane under the Parallel relation, under GCD Relations.
You can use the double arrows, 
and 
, to move all a form’s surfaces between the Available column and Surfaces in Form column—select a form GCD in one of the columns and click a double arrow.
and , to move all a form’s surfaces between the Available column and Surfaces in Form column—select a form GCD in one of the columns and click a double arrow.Note that the form must not include any disconnected surfaces, that is, any two surfaces in the form must be connected to one another by a sequence of surfaces all of which are in the form.
8 Re-extract geometry.
To create a new form:
9 Click the Form Definition tool, 
, in the toolbar. The Form Definition dialog appears.
, in the toolbar. The Form Definition dialog appears.10 In the Viewer or in the left pane of the Form Definition dialog, select the forms that you want to include in the new form, and then use the arrow to move them to the Surfaces in New Form column.
11 Re-extract geometry.
Modifying the Subtype of a Form
You can change a form’s subtype by editing the SubType property in the Geometric Cost Drivers pane, or by using the Form Definition dialog, provided you are connected to your part’s CAD model:
Be sure to re-extract geometry after you change the subtype.