cloth - Simulate a cloth surface
Displacement "cloth" "freq" n "depth" n
float freq=500, Ks=0.02
This shader produces a cloth-like perpendicular weave pattern. The freq parameter changes the frequency of the threads (higher values mean the threads are closer together), and depth controls the height of the threads. The surface aliases pretty fiercely, but real cloth actually produces a somewhat similar effect, so it looks fairly realistic.
Remember to set the displacement bounds attribute when using this shader.
Pixar Animation Studios