## 2 Proposed Simulation Framework
### Module 1: High-Efficiency Modeling of Temporary Hospitals
#### 2.1.3 Evaluating the Design Schemes of the Air Outlets and Fresh-Air Intakes  
In this design phase, the detailed drawings and BIMs (e.g., SketchUp model, Revit model, or AutoCAD model) of the temporary hospital can generally be obtained from the corresponding design agency. Hence, the data transformation from the information model to an FDS model can be easily realized through Pyrosim [35] and the FDSCenerator program. Pyrosim is a popular pre-processing program for FDS. Figure 4 shows the detailed workflow of the data transformation. The information model developed in widely used 3D modeling computer programs (i.e., AutoCAD, SketchUp, and Revit) are first exported to an intermediate file (i.e., DWG, FBX, and DXF file correspondingly), which is then imported into Pyrosim to generate the FDS model that only retains the geometries of the building components. Subsequently, the FDS model generated by Pyrosim is imported into the FDSCenerator  
Figure 3: **(a)** Huoshenshan Hospital and **(b)** Leishenshan Hospital under construction (figures are from [[https://finance.sina.cn/2020-02-05/detail-iimxyqvz0523673.d.html](https://finance.sina.cn/2020-02-05/detail-iimxyqvz0523673.d.html)]([https://finance.sina.cn/2020-02-05/detail-iimxyqvz0523673.d.html](https://finance.sina.cn/2020-02-05/detail-iimxyqvz0523673.d.html))). Figure 2: GUI of the FDSCenerator program. through the \"reading\" function mentioned above, and the other information required by the CFD simulation can easily be supplemented in the FDSGenerator. By employing Pyrosim and the developed FDSGenerator program, a complete model conversion, capable of containing all the geometrical and other relevant data, is achieved to transform the information model to an FDS model. 1.4 Evaluating the Impact of Exhausted Harmful Air from a Temporary Hospital on the Surrounding Environment  
The impact of exhausted harmful air on the surrounding environment needs to be evaluated quantitatively before the design of the temporary hospital is completed. In this design phase, two challenges must be addressed if there exists a large number of old buildings in the target area. (1) Since the target area may have buildings designed by different companies and constructed over different years, it is challenging for engineers to collect detailed drawings or BIMs of all the surrounding buildings in a short time. In addition, it is highly possible that a few old buildings around the proposed temporary hospital lack detailed drawings, which introduces more challenges relating to the collection of building information. Thus, the modeling method introduced in Section 2.1.3 cannot be used directly to build the FDS model for the target area. (2) The surrounding buildings may have various complicated shapes, which cannot be easily modeled through the FDSGenerator program. To overcome the abovementioned difficulties, a high-efficiency modeling method based on BIM and geographic information system (GIS) data for the FDS model of the target area is proposed. The workflow of this method is shown in Figure 5. Firstly, the shape file and corresponding plot scale of the buildings lacking drawings and BIMs can be easily obtained from public map sources (e.g., OpenStreetMap ([[https://www.openstreetmap.org](https://www.openstreetmap.org)]([https://www.openstreetmap.org](https://www.openstreetmap.org))), Google Maps ([[https://www.google.com/maps](https://www.google.com/maps)]([https://www.google.com/maps](https://www.google.com/maps))), and Baidu Maps ([[https://map.baidu.com](https://map.baidu.com)]([https://map.baidu.com](https://map.baidu.com)))). Simultaneously, if we know the height, \(H_{1}\), of a specific building near or in the target area, we can measure the shadow length, \(L_{1}\), of this specific building and the shadow length, \(L_{i}\), of any building in the target area using online maps such as Google Maps and Baidu Maps.