Richard/Bejaymac - Thanks, both suggestions work fine. But I don’t understand why changing u, v to s, t works? Surely if you’re not using tiling (or you’ve got horizontal/vertical tiles both set to 1) then s=u and t=v? I must be missing something here… if I had a penny for every time I said that… ;o)
mjc1016 - now that I know what I was doing wrong in DS the fun can start! Using bump/displacement and texture images sounds good (I think for the Poser render in the first post I must have had the equation plugged into the bump channel judging by the specular highlights). Several other ideas spring to mind - e.g. another sine function to add smaller strands to the strands we already have, etc.
Regarding cross-hatching (I guess you’re thinking woven rope, like if you Google images for “12-Strand Rope”?) I think the trickiest bit would be the mask for the layered shader - but not that tricky…
One last observation for now - this type of shader seems prone to moiré effects, especially if you apply it to e.g. a cable receding into the distance.