线框映射的中值面提取方法

Mid-Surface Extraction Based on Wireframe Mapping

为了提取薄壁类B-rep实体模型的中值面,提出一种基于线框映射的中值面提取方法.首先搜索模型中的面匹配对,构建面对之间的边界线框拓扑图,并利用中间线算法生成置信三维边界回路.然后选择面对中一张面做等距操作,利用三维边界线验证等距面结果,如果边界线能匹配到等距面中任意一边,则将该等距面作为中值面输出;否则利用N边面生成算法插值成中值面.最后将所有中值面缝合成壳模型,如果原始面对是邻接关系而中值面之间不共享边,则自动延伸中值面到对应中值面,使其保留邻接关系.实验结果表明,利用该方法可以快速、鲁棒地生成实际复杂模型的中值面,为后续有限元分析提供良好网格划分基础.

To extract mid-surface from thin walled B-rep solid model, a novel approach based on wireframe mapping is presented. Firstly matched face pairs are searched, and a wireframe topology graph between matched faces is constructed. Then trustable 3D boundary loop using middle-curve algorithm is generated. One face from face pair is offset and verified using 3D boundary loop. If any boundary edge can match same edge in offset face＇s edge, the offset face as mid-surface is output. Otherwise, a mid-surface by 3D boundary loop is created using N-Side surface method. Finally all mid- surfaces are stitched into a shell model. Experiments show that mid-surface can be quickly and robustly created from real complex model, and it make convenient the following surface meshing for finite element analysis.