When the offset of an edge represented by an ellipse or parametric curve intersects itself, the PGM will perform the appropriate trimming operation. This occurs when the offset distance is greater than the minimum radius of curvature.
The animation illustrates a case where trimming is required when an offset parametric curve self-intersects as a result of increasing the offset distance. In the initial sequence, no trimming is performed. In the subsequent sequence, the PGM trims the self-intersection.
The offset distance is then reduced such that the offset curve no longer self-intersects. The PGM restores the offset curve to its smooth original configuration.