How it works
The track is a closed smooth curve through your points. Each point has its own width, height and banking, and the track blends smoothly between them. Curbs appear on tight corners, the start line sits at point 1 and the checkpoints are spread evenly along the lap. The racing line is worked out like a real driver would take it: wide on the entry, clipping the apex, wide on the exit. Each point on it has a target speed from the grip of the surface, so you can see where cars brake and where they flat out.
Driving it
Switch to Drive and use the arrow keys or WASD, or the on-screen buttons on a phone. Space or Shift is the handbrake for drifting. Tick 3D chase camera, or press C, to drive behind the car over the real 3D track with its bridges and banking. Pick any car, or the one you tuned in the Car Handling Designer. Leaving the track slows you down. Pass every checkpoint in order to count a lap. The ghost car follows the racing line at its target speeds, so it is a fair benchmark for your own lap time and for the AI in your game.
Bridges and figure 8s
Raise a point with Height to lift that part of the track. Where the track crosses itself, one side must be higher, otherwise the tool warns you. In 3D, raised parts get side walls and pillars, and the PNG draws them over the lower track with a shadow.
Using the files
The GLB uses one unit per metre with Y up. The top-down view maps to X and Z. It contains the road, curbs, walls, pillars, the start line and a ground plane, plus empty nodes for every checkpoint, the start and eight grid positions, and the racing line as a line. The JSON file has the center line, the racing line with target speeds in metres per second, the checkpoints with their direction and width, the starting grid and the mapping from metres to pixels of the PNG. A 2D game can draw the PNG and use the same JSON with X and Z as its X and Y.
Can I use the tracks commercially?
Yes. The tracks you make are yours to use in free and commercial games.