UI to change road collision layers

[TheDuckCow]

Right now, the collisions are set up automatically in the same way that collisions are auto-generated using the automatic static mesh mechanism in the UI. However, it's clearly useful to be able to manage which layers are used.

The feature request here would be some setting to specify how and where these collisions are set up. One choice to be made is whether this is a per- RoadContainer setting, or if this is something that can just live on the RoadManager itself. In my mind, the RoadManager makes the most sense as you probably would just want to assign it in one place. It opens a question for what to do with prefab scenes though, the RoadManager might have to do some extra work on scene-spawning (if "save children" is off anyhow).

Short term workaround

You can also manually ensure the right collision layers are used today with a custom script. Just subscribe to each of your RoadContainer's on_road_updated signal which will be called anything a RoadSegment is created/updated. The body of this signal is a list of RoadSegments, from which you can get to each RoadSegment's individual collision mesh/static body where you can manually specify the collision shapes.