Constructing 3D railway scenes helps improve the railway information construction ability and the comprehensive railway management level.However,the existing modeling methods have disadvantages such as low flexibility in scene configuration,weak extensibility of scene objects and poor reusability of modeling knowledge.To enable multitype 3D railway scenes to be automatically constructed,a template-based knowledge reuse method was proposed in this paper.First,based on parsing of modeling operation characteristics and modeling knowledge expression,a modeling knowledge template was designed to store modeling knowledge and modeling operations in a parameterized way.The contents of this template were described in terms of semantic information,geometric information,topologic information and reference system information,and the method for instantiating the modeling knowledge template was proposed.Second,a scene configuration template was designed to organize the instantiated modeling knowledge files and scene objects.By the use of a flexible tree structure,the scene configuration template enables extensibility of scene objects.Finally,the two types of templates were parsed in terms of scene organization,linear referencing information,geometric and topologic relationships,and semantic descriptions.In this way,different types of 3D railway scenes were generated automatically.After a prototype system was developed,experiments on automatic modeling of two 3D railway scenes were carried out to verify the template-based knowledge reuse method.The experimental results show that the proposed method can be used to generate multitype 3D railway scenes automatically.With this method,model combination can be configured,model types can be extended and modeling knowledge can be reused.
Heng ZhangJun ZhuQing ZhuHua QiChangjin WangZujie HanYa HuXinwen Ning
