Question: What is fog of war?
Question 2: What is it used for?
Thank you!
(just to keep this short)
1- The transparent gray "fog" over terrain you have seen before, that is not currently seen by your units. Buildings you have seen in the area are visible, and units are not. Any changes that occur here are not shown unless you bring a unit to the area and uncover the fog of war.
2- It is used to show terrain and buildings you have discovered after you have left the area.
I belive he was refering to the fog of war Layer in Staredit.
If you remove the dark part on the fog of war layer, the map will appear to have been already explored in those areas. Hence fog of war.
Fog of war isn't used that often, (that im aware of). If you were making a melee or a rpg map then you may choice to show the players the terrain, so they would know what it is like before they go there.