| 摘要: |
| 提出了一种基于二维轮廓线与超二次曲面型元球模型的造型方法,以实现简单、快速三维模型原型构造. 给定一条二维轮廓线,首先使用圆或椭圆去逼近它.然后对每一个圆或椭圆设置第三个维度的参数,能够获得相应的超椭球体型元球.最后混合所有元球的场,并对所有元球的形状参数进行优化,得到一个解析的元球隐式曲面.通过调整元球的位置或形状参数构造出的曲面能够方便地实现形状的修改.模型的不同组成部分可以在不同的投影平面上勾画轮廓线相似地进行设计.该造型方法支持简单的建模操作,如布尔加、减或准扫成体生成,以生成各种复杂形状的模型. |
| 关键词: 二维轮廓线 隐式曲面 元球 建模 形状逼近 |
| DOI：10.3724/SP.J.1001.2011.03943 |
| 分类号: |
| 基金项目:国家自然科学基金(60970097, 60933007); 国家重点基础研究发展计划(973)(2009CB320801); 浙江省科技计划 (2009C33001); 浙江大学CAD&CG 国家重点实验室开放课题基金(A0805) |
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| Extended Metaball Modeling Technique with 2D Silhouette Curves |
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LIU Sheng-Jun1, JIN Xiao-Gang2, LIN Jun-Cong2, FENG Jie-Qing2
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1.School of Mathematical Science and Computing Technology, Central South University, Changsha 410083, China;2.State Key Laboratory of CAD & CG, Zhejiang University, Hangzhou 310058, China
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| Abstract: |
| This paper proposes a simple and efficient method for creating three-dimensional prototypes based on sketching silhouette curves and super-quadric-surface metaballs. Given a silhouette curve, it is first approximated with a set of circles or ellipses. By introducing the third dimensional parameters, a super-ellipsoidal metaball is received for each circle or ellipse. Finally, an analytic implicit surface is constructed by summing the fields of all metaballs and optimizing all parameters. The resulting shape can be conveniently modified by adjusting the positions and shape parameters of metaballs. Different components of a model can be similarly designed by sketching on the different projection planes. This method supports simple solid modeling operations, such as adding, subtracting, semi-sweeping, and is able to generate variants of shapes easily. This method can be applied to designing prototype in the conceptual design stage for computer graphics or computer aided design applications. |
| Key words: 2D silhouette curve implicit surface metaball modeling shape approximation |
