While blackening the edges of the displacement map seemed to work for the door, I am really having a problem with the ramparts. I have carefully gone over this edge in the map in photoshop with a round 10pixel brush and saved it as a bitmap, then gone into the UV editor and made sure the 2 lines describing that chamfer in the middle are right in the middle of the thick black line, but still I get splitting along the edge. is there something I am overlooking in displacement maps... some way to get the edges to stay joined together perhaps?