Node.collideWith() question

That unsupported type exception will indeed be because Map.Wall doesn’t implement Savable (I’d suggest just make the interface Interactable extend Savable).

That said @pspeed’s suggestion with the Lemur library looks really nice! Assuming your picking is triggered off a mouse click* then that’s probably the way to go

*I use picking for all sorts of other things, like if a sensor or mob can see things