With Unity's terrain creator, I can't simply make a "hole" on the mesh.
I don't know how I would make cave-like structures other than using "rock" meshes for the roof (wich will indeed look weird) or using portals (wich I always have problems with -- the teleportation isn't thruly smooth and there's always a small "jump". You know, not like a fluid thing.
How can I make caves in terrain with Unity?