三维场景中基于视口空间的拾取算法  

Algorithm for Picking in 3D Scenes Based on Viewport Space

作　　者：朱明亮[1] 董冰[1] 王祎[1] 谢步瀛[1] 

机构地区：[1]同济大学建工系虚拟建筑教研室,上海200092

出　　处：《工程图学学报》2008年第2期94-97,共4页Journal of Engineering Graphics

摘　　要：提出一种基于视口空间的快速精确的拾取算法。算法的核心是将物体的包围盒投影到二维空间,在二维坐标系下进行拾取判断。用OpenGL实现该算法,并与经典的射线法在拾取的精度、速度及适用范围等方面进行了比较,结果表明,该算法全面超越了射线法。采用层次OBB(方向包围盒)结构管理复杂场景,引入视锥剔除技术,对算法进行优化并应用于施工仿真项目中,取得了很好效果。A fast and accurate picking algorithm based on viewport space is presented. The key point of the algorithm is projecting the bounding box of an object to the 2D space in which picking judgment is processed, The algorithm is implemented using OpenGL and compared with the traditional ray picking method. Results show that it transcends the latter on feasible scope, accuracy and speed. A hierarchical structure, OBB Tree （oriented bounding box tree） is introduced to organize models, and also view frustum clipping is used to optimize and accelerate the algorithm. It has been incorporated in a construction simulation project and works well.

关 键 词：计算机应用 拾取算法 视口空间 方向包围盒 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]