In most cases, exporting everything in your geometry as a single STL file is the simplest and most time-efficient way to upload a geometry to SimScale for a Pedestrian Wind Comfort analysis. However, there may be occasions in which you wish to upload an STL with different layers, which makes it easier to hide and show geometry, visualize different parts (such as trees or road surfaces), or to make selection easier using our bulk face selection methods.
Typically, there are a few programs that correctly export multiple objects and faces as separate STL parts, and therefore for most common CAD or modeling tools, you will need to do some geometry post-processing before importing to SimScale.
However, the following section explains a rather simple method where the different STL files can be merged together without any external software while still being able to work with the different layers separately.
The Simple Merge Method
This method allows you to merge the STL files generated in tools like Rhino, Sketchup, ArchiCAD, etc. directly in Windows OS. Follow these steps to upload the merged STL files hassle-free:
- Export each layer of the model (buildings, trees, terrain, etc.) as a separate STL file. Each file should be exported in the ASCII format. All the resulting STL files should be saved in one folder. This document explains the export process in detail.
- Open the folder containing the saved STL files and while maintaining the SHIFT button on the keypad right-click and select either “Open command window here” or “Open Powershell window here”.
- Now copy-paste and execute the below command:
- copy *.stl Allfiles_merged.stl (for command window)
- cat *.stl | sc Allfiles_merged.stl (for PowerShell)
- Import the “Allfiles_merged.stl” file to SimScale.
This whole process has been explained in this video.
The end result will an STL that can be uploaded to SimScale and maintains individual layers that are both hide-able and select-able. For more information on how to export and how to upload an STL file, refer to this document.