@ tommy8: There are scripts that turn the terrain and water plan off and on for this at the moment.
goindoors.lua and gooutdoors.lua. Assign them to a trigger zone.
And this thread may interest the OP.
https://forum.game-guru.com/thread/213241Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit