Did you use extrude nurbs or a boolean? if so those are best avoided they are very untidy....the best way to do that would be start with a plane and make a 4 vertical cuts with the knife and one horizontal, then delete the middle portion so you are left with u shape upside down...now take the inside points and pull down to get the sloping shape...now in polygon mode extrude it....after you have done this the face of the wall has all the polygoins selected but you need to disconect the other polygons so go selection/ invert ....then go structure/ edit surface/ disconnect...remove the check mark and it will disconnect (split) all the poygons to give you sharp edges yet leave the front face ones intact (they don't need to be split)....hope that helps, uvmapper is great for fixing that kind of problem but with other models with curves you have to be more selective at what you split/disconnect so you can keep a smooth surface on a curve yet have a sharp edge where needed.......Steve