As constraints are created the Parametric Design module may need to create points and construction lines to serve as reference geometry. For example, when Design Intent Capture is enabled and LINE PARALLEL is invoked construction lines are created between the original and new lines, so that the two lines will remain both parallel and the same length.

Invisible Geometry is managed completely by the Parametric Design module. Whenever operations such as DELETE, MODIFY, or STRETCH are performed on real geometry any necessary changes are made to invisible geometry.