This is interesting. I personally have no interest in a Squeak Through-like mod that alters the whole game, but I have wanted some way to add circular collision to just trees. And maybe rocks. I think the right application of CollisionMaskConnector::not_colliding_with_itself would let us use native collision for some entities and non-native collision for others.

Theoretically we might change collision layers i guess, to achieve that too. It might also fix SpaceAge mech armor's flying animations.

Anyway that is rather big change/attempt and i don't want to get into it right now xD I just finished some more basic fixes and rewrites today. It was colliding even with AAI zones individual tiles (as entities). Personally i like the way it works, even if things like train wagons have even cheatingly small collision right now.

But the code now allows making individual exceptions like AAI vehicle depots, or some hidden constant combinators for advanced mod entities, and do it right in mod settings.