Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding Troubleshooting Help removing the floor.

You can cut the terrain from the Terrain Toolbar. It's the icon with the scissors (next to the 5):



It works like other terrain painting where left mouse click will cut the terrain and right mouse click will restore it should you ever want it back.