What do you guys think is the best way to place terrain governed by line-of-sight? Instead of building the whole layout first, I'd like my players to know only what's coming next when a door is opened, or as they turn a corner, bit like a fog-of-war.

I have tried this in the past in two different ways:

One was to cover individual rooms with sheets of cardstock cut to fit the room size/shape. Then remove one cover at a time.

Another was literally to individual rooms to the table one at a time. This is more 3D than the previous option, but requires much more space off the table.



A third option would be to literally build it as you go. This would work alright with focusing mainly on ground tiles and props (the 2.5D sort of build)

Those are the only ideas that I have used in regard to this before. They all worked alright, but in the end, now I just fill out my whole table with terrain and tell the players to not metagame. I wait to place props and minis though.