How do I stop my directional light ("the sun") from penetrating/bleeding into my caves?

[phil123456]

@anonymous_user_ea18bd8d

[SOLVED]

For anyone reading this in the future this is what I did:

http://i.imgur.com/GUeevOn.png

I placed a hollowed out box, drawn with BSP, around the entire cave. I then cut out the entrance to the cave with a completely subtractive box.

On the inside it’s dark as night

it does not work at all…why would it

bsp’s dont interact with light anyway