使用二维轮廓线的扩展元球造型技术

Extended Metaball Modeling Technique with 2D Silhouette Curves

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.此方法能够广泛地应用在计算机图形学或计算机辅助设计领域中的概念设计阶段的原型设计工作中.

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.