基于TIN数据三维地质体的折剖面切割算法

为有效分析地质模型的内部结构,研究直接利用折切面对模型数据进行几何切割的算法。该算法面向基于TIN数据表达的三维地质体,包括"折剖面的生成"和"被切割地质体的拆分"两大关键步骤;采用向二维平面投影的策略,将复杂的切割转化为交线的快速连接、三角形重新剖分和点与多边形的包含测试等简单操作。对不同复杂程度的三维地质模型进行切割实验,发现化繁为简和二维投影策略极大地提高了算法效率。

Zigzag Section Cut Algorithm Based on 3D Geological Objects Represented by Triangulated Irregular Network Data

So as to analyze the interior structure of geological model,zigzag section cut algorithm,which cuts the model geometrically and directly with zigzag section,is studied.Focused on 3D geological objects represented by Triangulated Irregular Network(TIN) data,the algorithm consists of two key steps:the generation of zigzag cross-section and the partition of geological bodies being cut.When realizing the algorithm,the strategy of projection to 2D plane is utilized.It converts the complicated cutting problem to several simple operations,such as the quick combination of intersecting lines,the re-triangulation of original triangles and the inclusion test between point and polygon.The experiment results gained by several cuts to 3D models with different scales,show that the conversion and projection have raised the efficiency of the algorithm evidently.The practical application of the algorithm in visual analysis of engineering geological model for some area in Beijing is displayed.