Remove part of a plane I am trying to build a pool on top of a plane, the pool goes below the plane, How can  I remove the part of the plane that is in the pool?
You can Tab into Edit mode on the plane and use the Knife tool to trace the part of the plane that you want removed. Press K to activate the knife tool and left click to create points, to close a shape, simply left click on the starting point. You can also use right click to cancel a cut if you make a mistake.



Confirm the cut with Enter and there should be a hole in the plane.