one-sided vision

[Landy]

Hm, dunno if it's correct name for this, but i have a little problem.
As you see down there:

Huntress doesnt see what is up there, it's hidden in fog of war
And here:

There is no fog of war, because warcraft doesnt calculate heights for custom hills and stuff.
So here goes the question, is there a way to apply same sight blocking to custom mountains\hills? Like one-sided sight blockers.

 

[Dark Soul]

Line of sight blockers in doodads.

 

[Landy]

yeah, but if u use sight blockers, units who stay on top of the mountain won't see anything down there

 

[idodik]

Assuming that there's no way to change the terrain to help you at that point, I think that the only way is to create visibility modifier regions.
It would be REALLY REALLY complex but oh well.