Say I have a terrain.
And I have cave
And skylight on top of it.
With current setup my cave will be lit by skylight. Even though it is big cave, and there no chance that skylight will ever reach it (in reality).
Fully occluded sky light is probably beyond realm of possibility right now.
But what about something like light volume ?
What Light Volume does, it will cut off all lighting, and instead it could provide it’s own lighting (ambient).