Research On Data Analysis And Visualization System Based On IFC

As the basic framework of building information analysis system established by the Ministry of architecture for more than ten years,BIM Technology has been used as the basic tool of building information analysis system at home and abroad.At present,BIM Technology has been used as the basic framework of building information analysis system for the whole life cycle of the Ministry of architecture.For the existing IFC data analysis tools,problems often occur at runtime.For example,some tools only support version ifc2x3 and do not support the latest version of ifc4.Secondly,some tools do not support the analysis of all types of information because they do not have long-term maintenance,such as the INVERSE attribute of IFC data.At the same time,for the complex reference relationship of IFC data structure,there is a lack of applications that can visually analyze IFC data,Therefore,in view of the above problems,it is of great significance to develop IFC data analysis tools.For the existing systems that can visualize IFC data in three dimensions,they can often perform conflict detection between electromechanical(MEP),building and structural models.However,the application of IFC data in MEP design is still relatively small.Taking the ventilation system as an example,most of the current studies often lack detailed performance analysis of the whole system,such as the length of the pipe path from the air conditioning unit(AHU)to the air outlet,the air balance at the diversion point or joint fittings,and the total pressure loss in the critical path.At the same time,for the interactive visualization of MEP calculation results and BIM model,these systems still have deficiencies.Therefore,it is necessary to develop a system analysis and interactive visualization system based on IFC.Based on the above problems,the main research contents of this paper are as follows:(1)IFC data analysis tool(Ifc Web Explorer)is developed.Firstly,the Schema standard file is parsed,and all attribute names of IFC entities are obtained through continuous retrieval through inheritance relationship.After that,the IFC file is parsed line by line,the class name,p21id and attribute string of IFC entity are matched through Python regular expression re module,and then the attribute string is divided according to comma to obtain all attribute value sets of IFC entity.Finally,integrate the Schema of the first two steps with IFC,store each attribute name and attribute value of IFC entity through one-to-one mapping relationship,and get the map format of each IFC entity.On this basis,build a lightweight network server through the flask framework,match the strings in five states with regular expressions on the client,and return the matching corresponding information in all map entities through j Query Ajax,And displayed in tree form.The experimental results show that the tool supports versions ifc2x3 and ifc4 for data analysis of IFC,which improves the current IFC analysis tools such as IFC JS can not resolve the INVERSE attribute problem,and supports the cross platform tree display of data.(2)BIM model and duct pressure loss visualization system(Ifc Pressure Viewer)are developed.Firstly,the critical path class of ventilation system is defined,and it is proposed to describe the ventilation system from different levels of critical paths.Then,the division method of critical path of ventilation system is described in detail.On this basis,combined with the data analysis of IFC,the first research content,the geometric information of each ventilation system equipment is extracted,including sweptsolid and BREP models.Then the spatial coordinates of the model are transformed for BREP model,It is also necessary to use Bowyer Watson algorithm to Delaunay triangulate the scattered point set of the whole model,and finally based on three JS realizes the three-dimensional visualization of the whole ventilation system.For the non geometric information of the equipment,the divided critical path will be imported into the chart data plug-in ECharts as user-defined non geometric information,which will be visualized in the form of pressure loss distribution.For the non geometric information existing when exporting IFC files such as size and air volume,it will be transmitted to the client in the form of JSON,and visualized in the form of system box and attribute box.Interactive visualization is based on the p21id stored in local Storage by interval query.Then,according to the definition of air duct element and node element flow direction,a user-defined addition method of node pressure loss is proposed.The experimental results show that the system makes up for the defects of BIM model system analysis in the MEP design of the previous system,realizes the integration of the pressure distribution performance data of the pipeline system with the BIM model,and solves the problem that many BIM tools can not calculate and output the pressure loss in all directions of the nodes of the ventilation system.The proposed method of adding pressure loss to the nodes can directly interact with the three-dimensional model.