改进Catmull-Clark细分算法及其在船用螺旋桨设计中的应用

基于舰艇作战或巡航时隐身性能的需要,针对舰艇关键零件的设计和加工制造现状,结合应用日益广泛的细分曲面造型方法,以Catmull-Clark细分算法为基础,提出一种基于网格边光顺程度计算的自适应细分算法。将该算法应用于船用螺旋桨的设计数值实验,由建模软件3DS MAX及其内部编程语言MAXScript来实现,并将实验结果与原始的Catmull-Clark算法细分结果、传统的顶点或边曲率法自适应细分结果进行了比较。数值实验结果表明,在满足零件设计现实需求的前提下,该自适应细分算法能较好地减少网格数量:当边的光顺度阈值取为0.825时,网格数降低了约28.83%,可提高计算速度,减小存储空间。该算法能克服以往基于均值计算的自适应算法存在的区分能力不足的影响。

An Improved Catmull-Clark Segmentation Algorithm and Its Application in the Design of Marine Propellers

To improve the stealth performance of naval ships during combats or cruising,an adaptive sub division algorithm based on the Edge Smooth Value of meshes was proposed in this paper to refine present techniques of critical ship parts design and manufacturing.This algorithm is based on the Catmull-Clark subdivision algorithm,and incorporates the increasingly popular application of subdivision surface model ing.To test the algorithm,several numerical experiments of marine propeller design were conducted resort ing to the modeling software 3DS MAX and its internal programming language MAXScript.The experimen tal results were then compared with the original Catmull-Clark subdivision algorithm as well as the conven tional vertex or edge curvature-based adaptive subdivision algorithm.It has been found out that the new adaptive subdivision algorithm greatly reduces the total grid number：when the threshold of Edge Smooth Value is set to 0.825,a deduction of 28.83% occurs in grid number,which significantly improves the cal culation speed and reduces the required data storage space.Also,this algorithm can solve the inadequacy found in other adaptive algorithms for distinguishing.