1. A method for constraining a graphical model in a CAD system, comprising: receiving a graphic model in a CAD system; receiving a selection of a symmetric constraint by the CAD system; receiving a selection of a first curve of the graphic model by the CAD system, the selection indicating a point on the first curve; receiving a selection of a second curve of the graphic model by the CAD system, the selection indicating a point on the second curve; determining a user's intent by the CAD system; applying a symmetric constraint between the first and second curves, by the CAD system, according to the user's intent; and storing and displaying graphic model by the CAD system.