基于VTK的三维地质建模方法研究

Study of 3D geomodeling method based on VTK

不规则三角网(TIN),广义三棱柱(GTP)和四面体(TEN)是广泛应用于钻井三维地质建模的数据模型。本文重点研究TIN-GTP-TEN混合建模方法,通过引入VTK作为可视化工具,利用VTK类库中的相关建模函数以及其自身数据结构以点索引号集合来表达任意几何体的特点,对基于钻井数据的传统三维地质建模过程作了一些改进。例如,通过在TIN构造方法上添加顶点排序步骤,使TIN拓扑信息更加丰富。简化了GTP模型结构,使原来的6组拓扑关系只保留两组,分别为修正的TIN-GTP和GTP-顶点,其中修正的TIN-GTP拓扑关系能实现GTP快速剖分为四面体,用于模型显示和空间操作分析。此外,利用VTK提供的蝶形细分方法来得到更加精细的模型体。实验表明,本文得到的TIN-GTP-TEN混合模型可以很好地完成整个模型系统,也能实现线,面及体的快速查询,模型数据的维护和更新也更为简便。

Triangular Irregular Network（TIN）,Generalized Tri-Prism（GTP） and Tetrahedron（TEN） model are widely used for 3D geological modeling.In the paper,we propose a mixed method with TIN-GTP-TEN model and made some improvement to the existing modeling approach for borehole data,by introducing VTK as visualization tool and utilizing its class library as well as data structural features.For example,sorting vertices is added to the construction of TIN with borehole data,which makes TIN topology information much richer.The existing GTP model is modified and simplified.In revised GTP model,only two topological relations,i.e.TIN-GTP and GTP-Vertices are remained.The application of topological relation between modified TIN and GTP for quick division from GTP to TEN,greatly simplifies the display and interactive operation of the model.In addition,the revised butterfly subdivision method from VTK library is used to get a much smooth and visually pleasing solid.The results obtained with the modified TIN-GTP-TEN model show that,the geological modeling method proposed in this paper is more feasible and efficient,which can be applied to do quick query of line,face and body,and also simplify the maintenance and update of data.