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| Large surface fitting and trimming techniques forN-sided regions filling |
| XU Jin1,2, KE Ying-lin1 |
(1.Departmentof MechanicalEngineering, Zhejiang University, Hangzhou 310027, China; 2. School of Mechanical and
Automotive Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China) |
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Abstract A new method based on large surface fitting and topology recovery techniques was proposed to deal with the problem of N-sided regions filling in reverse engineering, which appears occasionally in the reconstruction of complex CAD models. Curveswere constructed on the surrounding surfaces of the N-sided region, and subsequently the surrounding surfaces were trimmed to obtain a large quadrilateral region which including the N-sided region. Then, all the surrounding surfaces were evenly sampled and a B-spline surface was constructed, by interpolating the discrete boundary constraints and approximating all the points in the quadrilateral region. Finally, the B-spline surface was trimmed and all the surrounding surfaces were refitted subjected to the constraints of points sampled from the B-spline surface. The final model is approximate G1 continuous in global sense, and it keeps the same topology as the original model．
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Published: 26 February 2010
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N边域大区域曲面逼近及其裁剪计算技术
针对反求工程中出现的N边域问题,提出一种用大四边域曲面进行曲面逼近,再对其进行裁剪计算的N边域填充方法.在N边域周围曲面上构造曲线,对周围各曲面逐一裁剪后得到一个包含N边域在内的空间大四边形区域.将周围曲面分别进行均匀离散化得到大区域内完整的离散约束点,拟合一张B样条曲面，使得它插值于大区域边界处的离散位置和法矢约束，并且逼近大区域内的所有约束点.将大区域曲面进行裁剪得到用于填充N边域的裁剪曲面,并以大区域曲面为基准对周围各曲面进行重逼近,使得填充后模型各曲面之间达到近似G1连续,同时在整体上保持了模型原有的拓扑结构.
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