This is truly amazing, you are not alone with photogrammetry and creating a track with a height map, I have already tried to create my own version of the Chimay track. I have a few questions, I'm really interested in how you can get the scale correct with the height map. I know how to distort my mesh, but the scale is not correct relative to Z. You can recreate a Google Earth Pro copy from a photo or with Blender's GIS plugin. But with this method the route of the road is not correctly adjusted either ^^ The south of Belgium is entirely scanned by lidar, so I can create the Mariembourg Karting track, the Chimay & Mettet "Jules Tacheny" track . I'm thinking of 3 or 5 hill climbs near my house. I've had my project in mind for 5 years, it's crazy how connected we are all
What the drone do you have? I've shared BeamNG screenshot, Terrain editor is funny to use
This can be useful : https://en.wikipedia.org/wiki/Euler_spiral that's how some road is created... Covadis for autocad can be usefull to understand how ingeneer create roads.