Hammer.horror: Not sure about the bump, will check that out, cheers for pointing that out, you say the physical sky is fine for clouds etc, but how would you go about making clouds? I know how to make them from nurbs spheres and play about with the color and alpha gains but they don't seem to render right in mentalray, you get a semi-transparent sphere thingy around them. Or does anyone know if there's an actual setting to make clouds in the physical sky?

Actually,I've just realised that the grout between bricks does stick out slightly, it's called pointing, helps rain run down the wall and not seep inbetween the bricks, but I'm going to try minusing the bump to see how it looks anyway!