Im using displacements as the ground of my map, And del all the other sides but the top of it. So doing that will it cause leaks? or will I have to box it in some how?
You need a nodraw brush at the bottom of your map somewhere touching the bottom edges of whatever you're using for sides.
and just to clarify, only making the top a displacement has nothing to do with it. Any brush with displacements (even on all sides) won't seal the map.
