Hi I am just migrating our face-to-face campaign of Princes of the Apocalypse to roll20 and I am trying to get in to all different aspects of this great tool. So, as for the fog of war feature... Is there any way to like prep this beforehand? I understand that the freehand tool is rather fast and it will work fine with that, however, I would love to be able to spend fifteen minutes before a session to prepare the maps and designate "segments" of fog of war that I then easily could reveal by just the click of a button.