Comments on: tips for rendering maya fur with mentalray

By: david

david — Tue, 31 Mar 2009 12:16:05 +0000

Thanks Mark. I emailed a more lengthy reply, but here's the short version.
Volume Fur and Final Gather do not work well together. Its like the fur gets illuminated from within and looks washed out and unnaturally translucent. I don't know a workaround, except for rendering the fur separately with no fg, and everything else black matteOpacity=0 so you can composite later.

By: mark.c.fain

mark.c.fain — Fri, 27 Mar 2009 18:52:41 +0000

Hey, great post. I'm having sort of the opposite problem with the fur that I'm using for a character's hair. I'm trying to get brown fur, but it keeps rendering with white streaks in the base color even when I turn the base color all the way to black. I have one spotlight and one ambient light in the scene. The spotlight is casting shadows and emitting global illumination photons. I'm loving the soft look of the volume fur, but everything I've tried to get the color right hasn't helped. If anyone has any suggestions, I'd really appreciate it. Thanks, Mark

By: deeppurple

deeppurple — Fri, 27 Feb 2009 00:33:05 +0000

Oh, how do you setup different render passes for fur and shadows? Thanks =]

By: deeppurple

deeppurple — Fri, 27 Feb 2009 00:32:11 +0000

Thanks, I found by upping the anti aliasing settings, it got rid of most of the flickering!

By: david

david — Thu, 26 Feb 2009 13:16:44 +0000

Flickering shadows are a real problem with fur. I've used much higher shadow ray, but it slows down the render. Usually I end up rendering different layers so that I can attempt to fix these kind of problems in post.

By: deeppurple

deeppurple — Wed, 25 Feb 2009 19:29:24 +0000

Hey David.

Thanks for the great tips! Getting some nice results.
What raytracing values are you using on your lights?

I rendered a quick animation with the fur being driven by dynamic hair, but got some flickering from the shadows I think.

My current values are 0.1 for light radius and 4 for shadow rays.

By: ytsejam

ytsejam — Sun, 18 Jan 2009 18:19:15 +0000

thanks david.

By: david

david — Wed, 14 Jan 2009 12:46:59 +0000

Yes, I broke the rules. I think it is ok to do that sometimes for creative reasons. This blog post was written after I worked on a project with fur, and to get a nice look we did adjust the gamma in the lens shader. In this project the animal was one of several render layers that were comped later, so we were free to do what was needed for the look we wanted.

I think it is common when using a linear workflow to render with gamma=1 (gamma=2.2 for preview only) and do the actual gamma adjustments in post, but I usually prefer to get as much of my "look" as I can in the render. Then I just do minor adjustments after.

By: ytsejam

ytsejam — Wed, 14 Jan 2009 12:28:15 +0000

Hi, David.
I have a question, You use the exposure photographic with the gamma to 0.500. But if I create a carpet for an interior and rendering in the scene, I cannot use the linear workflow, because I would have in truth to set the range gamma to 2.2.
Thanks ytsejam

By: david

david — Thu, 11 Sep 2008 12:34:02 +0000

chiax: I have not had the opportunity to use shave-and-a-haircut in my work so I cannot offer much help there. I dont think you can use the mentalray volume method. You must either use the primitives or the shave buffer render (which has its own depth map attributes).

I notice its been almost a week since your comment - maybe you could let us know how it went.