摘要
首先利用隐函数直线表达式的划分正负性质,既可分离出多面体的前向面,又可分离出与可见棱线有遮蔽关系的相关面,然后再利用隐函数平面表达式的划分正负性质,就可判定棱线上重影部分的可见性,从而实现全部隐线的消去。由于不采用传统的最大最小判别原理,它分离出的相关面更为准确,使无效求交的计算量大为减少。这种方法的数学处理精确、简便,提高了计算速率;数据结构简单,节省了存储空间;适用于由平面组成的任意形状的多面体,而且特别适用于以平面逼近的曲面立体。
First by utilizing the property of implicit functional expression of line dividing a region into positive and negative, not only front faces of the polyhedron but also the hidden relational faces relating to visible contoural edge can be distinguished. Then, by utilizing the same property of implicit functional expression of plane, determine the visibility of overlapping projection segment of contoural edge, so hidden line elimination can be accomplished. Because in this algorithm the maximal and minimal box principle is not used, the distinguishing of hidden relational faces is more efficient, and unnecessary calculations can be greatly reduced. Mathematical treatment of the algorithm is precise and easy, computing rate is higher data structure is simple, and computernmain memory requirements are less. This algorithm could be applied to any polyhedral systems.
