Research On Data Fusion Technology Based On Cloud-BIM

With the continuous adjustment of my country’s industrialization and information system,Building Information Modeling(BIM)technology has developed rapidly.However,the advantages of BIM technology in the entire life cycle of construction projects have not yet been fully reflected.The main reasons are as follows: The data storage of each participant in the construction project is chaotic,and the BIM standards in various places are inconsistent;Although the IFC standard provides the possibility for building data sharing,the transmission and rendering of its huge data system under the Semantic Web has problems,and the integration of geometric data and attribute data is not ideal;In the process of data conversion,data fusion and visualization,it is difficult for BIM models to maintain a balance between 3D geometric data,the richness of model semantic data,file conversion size,rendering adaptation performance,and application platform architecture;The operating environment of construction projects is relatively complex,and the traditional recording mode of construction material data is likely to cause data omissions,lag in transmission,and even calculation errors,resulting in the loss of the semantics of the building information model.In view of the above problems,the main research work of this article is summarized as follows:(1)This paper integrates the cloud computing system,software architecture classification and multi-dimensional data integration strategy for BIM services,and builds a cloud-BIM data fusion architecture according to the architecture idea of "high cohesion and low coupling".(2)The theoretical mechanism of BIM data conversion and data visualization under the semantic network is explored under the guidance of cloud-BIM data fusion architecture.In the stage of BIM data transformation,the BIM model is respectively transformed into gl TF data stream files with three-dimensional geometric data,a property database file with model attribute information,and a model structure tree file which can be used for manual scheduling of LOD model.In the stage of data visualization under the Semantic Web,the principle of reconstruction of the BIM-Viewer graphics lightweight rendering engine based on Three.js was discussed,combined with visible surface discrimination algorithms such as octree scene management and backward surface culling to improve graphics engine rendering performance;In addition,the application method of the ray casting algorithm in Three.js is introduced,and the vulnerabilities of the prototype HTML and viewpoint coordinate transformation are repaired.(3)Based on the combination of cloud-BIM data fusion architecture,BIM data conversion and visualization theory,material data flow model and constraint model,the PC-oriented "BIM data lightweight" plug-in and the Web-oriented cloud-BIM have been completed respectively,as well as the cloud-BIM data platform relying on the cloud server has been deployed.In view of the above work,this paper verifies the platform function through a Revit(building + structure)model of a residential building project.The verification shows that: in the stage of model transformation,the "BIM Data Lightweight" plug-in can automatically complete the lightweight conversion of model data,coordinate transformation,semantic mapping,gl TF data stream partition as well as other work,and the compression effect of the whole gl TF file stream is obvious;In the stage of data visualization under the Semantic Web,the model loading efficiency is high,the rendering frame rate is in a high range,and the manual scheduling of the LOD model works well.Further,through the selection of model components,the data of model attributes,engineering calculations and construction materials are automatically retrieved,and the physical memory curve tends to be stable during this process.In addition,the material business report and early warning prompt of the intelligent material management system module performed well and met the expected demand.In summary,the various functions of the platform have performed well,which proves that the theoretical mechanism and method strategies proposed in this article are effective and provide solutions for the sharing and integration of BIM data.