In this example, the design intent is to maintain a constant distance of 20 units between the centre of a sketched screw hole and an outer profile.
Initially, a 2D DCM dimension is applied between the centre of the screw hole and a line geometry on the outer profile. When the inner profile is dragged in a circle, the screw hole follows the unbounded geometry of the outer line (the unbounded line is shown in red). The 2D DCM has no knowledge of the higher-level design intent implied by the connectivity of the outer profile.
The alternative is to use the PGM to treat the outer profile as a loop, a higher level data structure only available to PGM-enabled 2D DCM users. The animation shows the effect of applying the same distance dimension to the entire loop instead of just to the individual line. Dragging the inner profile causes this distance constraint to transfer itself around the loop, maintaining the design intent and allowing the user to investigate sketch configurations far more quickly than would previously have been possible.