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| A mesh deformation technique for fitting to closed contour |
| ZHANG Yun-long, WANG Jin, LU Guo-dong |
| State Key Laboratory of CAD and CG, Zhejiang University, Hangzhou 310027, China |
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Abstract In order to enhance the flexibility and effectness of 3D modelling, a mesh deformation technique was proposed for fitting to closed contour. After users edited contours interactively, the preliminary mesh result was computed by multiple iterations of barycentric coordinate deformation, and then the region of interest (ROI) was obtained automatically by comparing the original mesh and the preliminary mesh results. Then, the Laplacian mesh editing method was applied to each ROI. In addition, the mesh vertexes on the contours were used as boundary constraints to make sure that the deformed mesh results fit well to contours, and the part of coordinates of preliminary mesh vertexes were used as additional constraints to avoid evident dent in the mesh deformation. Taking the minimal difference between the differential property of the original mesh and that of the deformed mesh as the objective function, the mesh was deformed by builting and solving a sparse and linear equation set. Experimental results showed that this algorithm was simple and intuitive in the interactive edit process, with no manual selection of the deformation region. Besides, it can reserve local features of the mesh, and avoid evident dent in mesh deformation when contours are dragged into the mesh.
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Published: 01 April 2015
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吻合闭合轮廓线的曲面变形技术
为提高三维模型造型的灵活性和效果,提出一种吻合闭合轮廓线的三维网格曲面变形方法.该方法在用户交互编辑轮廓线后,基于重心坐标多次迭代变形得到初步网格结果,将该结果与原始网格进行对比,然后自动计算网格变形区域（ROI）；对各ROI分别应用Laplacian变形方法,以轮廓线上的顶点作为边界约束以保证变形网格吻合轮廓线,以初步网格结果的部分网格点坐标作为附加约束以克服网格变形的明显凹陷情况；将变形前和变形后网格模型的微分属性之差最小作为目标函数,求解稀疏线性方程组来实现网格变形.试验表明：该算法交互过程简单直观,无须手工选择变形区域,能保持模型局部特征,同时能克服轮廓线往里拖动变形时出现的网格模型明显凹陷的情况.
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