## 3 Methodology
### Collaborative Management of Micro-Meso Information
#### 3.1.1 Format Conversion  
Currently, various BIM software has been developed. However, most of this software has its own model format. Although model information interaction can be carried out among some software, it is still difficult to carry out complete model mutual derivation and model integration. The Industry Foundation Classes (IFC) format is now being promoted internationally, and the major software vendors have developed corresponding data interfaces. However, the IFC format is still in the process of improvement. On the other hand, various software vendors have different development ideas for the IFC format interface. These reasons lead to attribute information (material, color, etc.) loss and even missing components in IFC format conversion [28]. Therefore, many enterprises and users begin to unify the information model file format by building model transformation plug-ins in different software, through the API (Application Programming Interface), so that different software can export the same file format. The plug-ins can be used to extract all kinds of information required by the user to make up for the lack of model information. Moreover, the participating units deliver the same file format, which saves the time and energy of the later staff for the induction and arrangement of different file formats so that the construction units of all kinds of engineering model formats have a unified management system. During the process of converting model file formats, corresponding plug-ins need to be designed according to the API interfaces of the BIM software used. Such plug-ins must satisfy the basic requirements as shown in Figure 5. Firstly, the plug-in's design architecture needs to be compatible with various common BIM software in order to ensure its universality in the engineering industry. Secondly, the plug-in needs to export the same model file format, facilitating the unified management of files by construction units and government units. Thirdly, the exported file format needs to be able to be imported into a GIS environment and fully express the important information of BIM models and components, ensuring the integrity of the main information of the project and preparing for the fusion and display of subsequent project scenarios. Figure 4: multi-scale information collaborative management method based on BIM. SuperMap GIS 10i (2020) offers a comprehensive set of spatial data processing and analysis capabilities that are highly suitable for handling the complex spatial information involved in construction projects. It has a proven track record in the field of urban planning and construction projects. It has been widely adopted in many similar projects and has demonstrated its reliability and effectiveness in handling large-scale spatial data. Its compatibility with various data formats and its ability to support multiple software interfaces make it an ideal choice for integrating different BIM software models. This flexibility allows for the seamless conversion and integration of model files from diverse sources, which is a key requirement in a multi-scale information collaborative management context. Taking Revit 2020 as an example, the unified target file format is the.udb format, which can be imported into the SuperMap platform, and the plug-in tool is called the UDB plug-in. The following is a brief introduction to the development process of the plug-in. Analyzing the structure and characteristics of the plug-in development in the Revit software. In the Revit software, there is a class library, called RevitAPI, that encapsulates internal commands in Revit. At the same time, RevitAPI provides a set of assemblies that provide interfaces for external programs. For example, the RevitAPI.dll assembly contains methods for accessing files, graphics, and parameters at the database level, as well as interfaces such as IExternalDBApplication.