How do I prevent hair flickering in Cycles?

Question

I'm working on a scene for a short film, and one of my characters uses Cycles strand rendering for hair. When I render out the animation, I notice the hair flickers like crazy and I'm not sure why.

Here is the video: https://www.youtube.com/watch?v=oF662SBlZpo

Here is the node setup for his hair: enter image description here

This becomes VERY apparent when the character is moving and not so much when he is still.

Does the hair flickr without shading? Could be a hair dynamics issue and not a rendering issue. — Mike Pan, Feb 18 '15 at 05:06
I'll do a test without shading. Also, I haven't enabled hair dynamics for this scene. — Danan, Feb 18 '15 at 05:27
I was just thinking, maybe it is caused by Z-Fighting of the particles, if you have children enabled, then try disabling or decreasing the number. Also be sure it is set to Interpolated. — J Sargent, Feb 18 '15 at 13:55

score 5 · Accepted Answer · answered Feb 18 '15 at 20:28

5

It could be your UV coordinates, which are "generated". Since they are probably calculated in world coordinates, moving the object also moves the UV coordinates. It could cause shimmering "noise".

I don't think your node set up is what you want really. You should use the hair BSDF shader. Put 2 nodes using hair BSDF, one for reflection (hair color), and one for transmission (hair translucency). Mix between them and you are done. Consider creating manual UV coordinates and not using generated ones.

Good luck!

answered Feb 18 '15 at 20:28

beiller

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Thanks @beiller! Changing from "generated" to "UV" did the trick for me! – Danan Feb 19 '15 at 04:12
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Cool good to hear! Keep in mind that it may change the way the hair colour is distributed. Happy Blending! – beiller Feb 19 '15 at 15:57

How do I prevent hair flickering in Cycles?

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