Controlling u and v directions of a noise or fractal?
a while back I had a tutorial, which I've now lost. It had a quick and effective way to bump the vertical grooves/styrations you see on teeth using a ramp, a bump shader and I think either a noise or a fractal shader.
What you done was, you altered the fractal (or noise) so that its noise went only in one direction (vertically), so you effectively get a rough striped effect. Then, using the ramp, you fade these out so that the bump is deep at the top and shallow at the bottom.
I've looked though at both the noise and fractal parameters, and can't see how I did this before. Can anyone help with these (or suggest that it may be another shader all together)?