Weird black checkerboard pattern on mirrored displacements Dear all, My map is symmetrical and contains displacements. On the initial build I copied and flipped one side. Now a long way down the road I became unhappy with some of the displacements so redid them for one side, deleted the corresponding ones on the other, copied and flipped. They sew in fine but the copied ones now display a back checker pattern on running the map. They display fine in the editor. All the displacements are using blendrockgoundwall004 and it's only those I have just copied that show this problem. Compiling with/without lighting does not solve this - though with lighting results in mad z fighting artifacts - even though there is nothing else in that area. If I destroy them and redo manually I don't have this back checker problem - but this will take ages and I won't end up with a symmetrical map. Any ideas?