MMK Driving Simulator

1. Export an arbitrary chosen area from OpenStreetMap as OpenStreetMap XML Data (ordinary .osm file) named map.osm.

2. Run osmsanitizer.py located in the CityEngine project in scripts folder using python3 by specifying the path to the downloaded map.osm file. This will output a sanitized version of the original map which includes only drivable roads and buildings, named map-sanitized.osm.

   python3 osmsanitizer.py map.osm
   

3. Create a SUMO network simulation using netconvert and specify as osm input map-sanitized.osm. The output of this tool is map-sanitized.net.xml containing information about the road network, such as lanes and their connectivity, as well as commands for driving vehicles (the latter is not considered by this guide).

   netconvert --osm-files map-sanitized.osm \ 
   -o map-sanitized.net.xml --output.street-names true \
   --output.original-names true
   

4. Open CityEngine and create a new project together with an empty scene. Copy the map-sanitized.osm and map-sanitized.net.xml in the data folder.

5. Drag-and-drop map-sanitized.osm in the empty scene. In the opened pop-up window select only the following options and click Finish:

   • Select/deselect all - all objects from the input are imported.
   • Map OSM tags - include the osm ID which is used to correlate between SUMO and CityEngine data in the export process.
   • Run Graph Cleanup Tool after Import - this is the only setting which does not alter important characteristics of the network elements such as osm ID and their position. If any nodes or segments are deleted in the CityEngine's import process or after that by the user, this will introduce inconsistencies with the map data imported in SUMO. If for some reason you want to change something in the map you have to either change the map-sanitized.osm or check the export output for warnings and decide how to solve them.
   • Create Street/Intersection Shapes from Graph

6. In the generated city model select the appropriate rules for every object in the scene and generate the textures using the Generate button.

7. To export the city model in Unity3D compatible format, firstly, select all shapes and go to File > Export Model and choose the FBX option. Use the default location (models folder) for all export files. Select Center button and note the x and z offset values, set y to 0. The exported files should be .fbx and textures.

8. To export the semantical description of the road network use the mmkexporter.py script (cityengine-mmk/scripts). In lines 340 and 341 specify the path to map-sanitized.osm and map-sanitized.net.xml (relative to CityEngine project's folder) and in lines 345 and 346 define the x and z offset which you noted from the FBX export in the previous step. Important: The script will try to determine automatically the offset between SUMO and CityEngine data but if this does not succeed a warning message will be displayed in the console and the user has to manually enter sumoox and sumooz values in lines 351 and 352 and pass them to the Exporter object. Start the script either by selecting Python > Run or F9. The generated file can be found in cityengine-mmk/export and it is called by default MMK_GraphExport.json.

9. Import files in Unity3D by following the steps in this order:

   • Create a folder named Assets/Models/<name of scene>.
   • Create another folder named Assets/Models/<name of scene>/Textures and copy all pictures from the models folder in CityEngine to this folder.
   • Copy .fbx file to Assets/Models/<name of scene> (the materials folder will be copied automatically).

10. Drag and drop the model to the Unity3D scene and add a BoxCollider to the ground of the scene. Next, change the scaling of the street model to (100, 100, 100). Attach to the model the Network.cs script and CarRoadDescriptor.cs script to MMKCar. In Network.cs specify the path to MMK_GraphExport.json and in CarRoadDescriptor.cs enter the name of the city model.