Study On The Method Of Complicated Curved-surface Parts' 3D CAD Mold Building

Usually, there are two ways to form the curve-surface, one is designing by CAD system, the other is reverse engineering. With the development of computer, the integration degree of CAD/CAE/CAM is higher and higher. How to build 3D CAD mold of a curved-surface part by designing and reverse engineering has been a researching focus. Some complicated curve-surface parts can be designed by CAD system directly, but there are still some other parts which are from practicalities, reverse engineering is a good way to get their CAD molds. Building CAD mold correctly is the basis of CAD/CAE/CAM integration.Parameterizing description is the main way to describe curve and surface in CAD system. People have found many excellent characteristics of the NURBS method, and taken it as the main description of curve and surface in many kinds of CAD systems.In this paper, an automatically parameterizing forming system of large marine propeller is developed, by using NURBS method, ActiveX automation of MDT and VB language.In order to rebuild the 3D CAD mold of a mouse by reverse engineering, a reverse system is built based on laser measure technique and the SolidWorks software, and a fairing method of curve is proposed to get a much more ideal mouse's surface, and a new way named two- fixed -point method is proposed to deal with multiple views' problem. Finally, the 3D CAD mold of the mouse is rebuilt correctly and fairly.