I've gotten it to work but mostly it seems by luck not by design. I have a terrain (let's say a park) that I want to disable enabling another terrain in exactly the same place but not the park. I have it so the players remained on the other terrain but I've made a few mods (I'm introducing a 3rd alternative terrain) and now the players fall through the ground. I have to assume the terrain collider is what everyone is standing on. I made the assumption that the terrains can be at exactly the same position. I've tried enabling the 2nd terrain before disabling the 1st terrain but that doesn't appear to make a difference. Is this a "frame" problem such at for a moment there is no collider active for the players to stand on? Regardless is there a way to swap terrain colliders? I'm trying to get it so I can switch out the park for other "scenery". And as I've said, I had it working but not solidly it seems.