Hi, thanks for all your suggestions: I don't think it's displacement: I've tried lots of different settings and none made a difference. Same with ambient occlusion, with it turned on the lines were still there just not so black. Haven't tried the shadow map thing, but will definitely experiment with this. However, in the last hour I've just had some success by altering my Bump Map settings to Map Strength 30%, Amount 0.001. This has significantly reduced the lines so much that if you didn't know they were there, you wouldn't really notice them. I suspect that with some further tweaking here, I might be able to both get rid of them altogether and get the surface texture I require. Once again, many thanks for all your help. Regards, Rob.