Thirdly,under the condition of maintaining the geometry constraint graph, the author researches how to show, add, delete and modify constraint to geometry constraint system, including the Undo/Redo mechanism.

• 再次,在对几何约束的约束网格图进行自动维护的前提下,研究了约束的显示、添加、删除和修改,从而可以使几何约束系统的操作变得完备,并实现了参数化设计过程中的Undo/Redo 机制。