Abstract: To build a 3D shape rapidly for production concept designing, a kind of sketch based solid modeling system oriented to industrial products shape design was put forward. The 3D curves were constructed directly by using the method of sketch curve principal direction estimation. Based on minimum energy of active contour models, the 3D curves were modified. The 3D curve whose spatial deviation minimized from original target curve was taken as 2D curve projection result, thus 3D freeform surfaces were designed through using methods such as edge exchanging and triangle-division. Finally, a pressure-based deformation method was proposed to modify and refine the surface. With this system, users could rapidly and intuitively design 3D modeling in interactive mode. The efficientiveness of algorithm and the feasibility of engineering were verified by a variety of different modeling test on self-developed software platform.

Key words: sketch, 3D curves, freeform surface, pressure deformation, solid modeling

摘要： 为满足产品概念设计的快速三维建模，设计了一种面向工业产品外形设计的草绘实体建模系统，通过估算草绘曲线主方向的方法直接构造三维曲线，基于动态轮廓模型最小能量算法对三维曲线进行修正变形；将离原曲线空间偏离最少的三维曲线作为二维曲线反投影的结果，进而利用边交换、三角细分等方法构造三维曲面；最后采用压力变形方法对曲面进行变形修正。该系统能够使用户以交互方式进行快速、直观地建模。自主开发软件平台，并进行多种建模测试，验证了算法的有效性和工程可行性。

关键词: 草绘线, 三维曲线, 自由曲面, 压力变形, 实体建模