In the Stretch Forming process group, this GCD represents a candidate for the direction from which the ram approaches the stock during the stretch forming process. For some parts (for example, saddle-shaped parts) the direction from which the ram approaches for transverse stretching is one direction, while the direction from which the ram approaches for longitudinal stretching is the opposite direction. So both the ram direction and its opposite are candidate approach directions (though only one is explicitly represented as a GCD).

aPriori chooses the ram direction as described in How the Default Ram Direction is Chosen in the Sheet Metal—Transfer Die chapter of this Guide.

When you select the GCD in the Geometric Cost Drivers pane, the ram direction is displayed as an arrow. You can manually override the ram direction if necessary. See Overriding the Default Ram Direction in the Sheet Metal—Transfer Die chapter.