摘要
裁剪曲面是基本图形交换规范(IGES)的主要内容,详细介绍了IGES文件中裁剪曲面的定义格式。在开放图形库(OpenGL)环境中,要求裁剪曲面外环必须是逆时针的,内环是顺时针的才能得到正确的显示结果,给出了平面任意多边形走向判定算法用来调整内外环的走向。此外,还给出了曲面控制点和裁剪曲线中直线段的调整方法,提供的实例证明了算法的有效性。
The definition of trimmed surface is main content of Initial Graphics Exchange Specification（IGES）. The format of trimmed surface description in IGES file is discussed in detail. In order to get the correct presentation with OpenGL, the orientation of outer loops must be counterclockwise, and inner loops must be clockwise. An algorithm to determine the orientation of arbitrary planar polygon is proposed to rectify the orientation of outer and inner loops. Furthermore, the way of adjusting the sequential order of surface control points and segmentation of cutting line to trim free-form surface are discussed. The examples show the algorithms work well.
出处
《工程图学学报》
CSCD
北大核心
2005年第5期150-154,共5页
Journal of Engineering Graphics
