Here is Alyson and her top, with the shader set for fully opaque fibers, at a density of .5.

(Note: There's a little more to this - I have a weave set up as a bump to give it some texture.)

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)