网格模型的局部编辑算法

提出一种新的网格模型局部编辑算法，该算法可以精确地控制变形区域的大小、边界和变形点的位移，克服了FFD及其改进算法的缺点．首先交互地定义一个附着在模型表面的控制网格；然后建立模型变形区域与控制网格间点的映射，再依据变形要求来编辑控制网格；最后根据映射关系反算出模型变形区域点的新位置．控制网格可以是参数曲面的控制网格，也可采用一般三角网格或预先定义的网格模板．为达到精确变形的目的，对模型与控制网格重叠的区域进行自适应细分．该算法计算简便、易于实现，并能达到很好的效果．

Local Editing Algorithm for Mesh Models

A local editing algorithm capable of accurately controlling the boundary of deformation regions as well as displacement of points on model surface is proposed. First, a control mesh attached to the model surface is built interactively, and using projection or other rules to establish the parametri-zation and mapping relationship between points on the model surface and control mesh. Then conforming to the required object shape, edit the control mesh interactively. The movement of control mesh makes the model surface deforming to the intended form. The control mesh may take the form of regular array of control vertices for parametric NURBS surface, general triangle mesh, or pre-defined mesh template. In order to precisely control deformation of the model, common area of the model mesh and control mesh are subdivided adaptively. This method involves simple calculations and is easy to implement. Experiments show that the algorithm is straightforward and can achieve good result.