Research On Integrated 3D Scene Modeling Based On BIM + GIS

With the development of science and technology,the main space for human activities is shifting from outdoor to indoor.Regardless of whether it is from a military or civilian perspective,for virtual scenes,an indoor and outdoor three-dimensional space should be established to meet the needs of corresponding action description and analysis.Traditional virtual scenes are built based on a 3D GIS,focusing on the organization and call of massive terrain data,the description of multi-resolution terrain and the integration of multi-source data,mainly expressing the outdoor terrain environment from a macro perspective,and lack of indoor space Related description.The BIM technology expresses the building and its indoor structure and equipment in a comprehensive and detailed manner,combining the three-dimensional visualization of the geometric model with rich semantic information.The advantages of BIM and GIS are complementary.The combination of the two can realize the integrated three-dimensional expression of indoor and outdoor spaces and realize the combination of micro and macro.This paper focuses on the modeling of integrated 3D scene based on BIM + GIS.The following contents are the mian research of this paper.1.In view of the big difference between the common data standards of BIM and GIS,a method for BIM data conversion and processing for GIS applications is proposed.Firstly,the differences between the common data standards IFC and CityGML in the two fields is analyzed.Then the conversion of BIM model geometric information is completed through the coordinate transformation and geometric reconstruction.Finally,the semantic information is filtered and mapped,and the model is multi-level LOD processed to complete the conversion of the BIM model.2.In order to improve the modeling efficiency of 3D GIS,the idea of parametric modeling of BIM is introduced,the parametric modeling flow of the scene is analyzed and designed,and the parametric modeling methods of 3D pipelines and roads are proposed.The two methods analyze the modeling characteristics of pipelines and roads respectively and use the cross-section as the basic unit to design the expansion of the corresponding structure,while emphasizing the matching with the terrain and the classification of the data LOD.Through this method,the parametric modeling of pipelines and roads is realized,and the efficiency of scene construction is improved.3.Due to that the BIM model does not match the multi-resolution terrain data and tilt photogrammetry data in the three-dimensional scene,the fusion scheme of the BIM model and the terrain and the three-dimensional point cloud is proposed respectively.First,the characteristics of terrain data and point data are analyzed.According to the LOD classification in the BIM model conversion,the fusion with the terrain is divided into two types,and the terrain fusion scheme is given from the plane and stereo angles.According to the scope of the BIM model,the integration with the three-dimensional point cloud can be divided into two types: the BIM single model based on data preprocessing and the BIM large-scale point cloud fusion based on the GPU.Through the above scheme,the effective integration of the BIM model and the terrain and the three-dimensional point cloud is realized,and the accuracy of scene expression is improved.4.Using the above method as technical support,BIM + GIS indoor and outdoor simulation prototype system was designed and developed.The system is based on the design framework,based on the OSGEarth SDK,through the application development of the C ++ language,the above methods are integrated,and the indoor and outdoor integration of integrated visual interaction,information interaction,interactive modeling and analysis applications 3D visualization of space.And for specific applications to achieve indoor and outdoor integration task deduction.