Geometry and NPC

[grassdunes]

Is there any way I could delete geometry from a zone in the client side? And would this allow me to use /setgrav -1 without mobs getting stuck in the ceiling if I delet it? Trying to come up with a way to have mobs warp all the way to the top of the zone when they are indoors or have a roof on top, but nothing has worked for me yet.