Re: Shading hair

["Daniel Rind" <daniel.rind(at)gmail.com>]

That the shader is too bright is because it's stacking three speculars on top of each other. I'll add scale sliders for the next version, for the time being you will have to use relatively dark specular colors.

 

Volumetric shadows should work just fine. In older XSI versions (4.2 and the like) there was a bug (either in XSI or mental ray, I never found out) where hair vanished from the detail shadow maps when the surface normal was set to (0, 0, 0), which is what my shader has to do. To get around that, I put the "Detail Shadow Hack" checkbox in, so you might try to check that if you don't get volumetric shadows right away. Note that this can lead to self shadowing artifacts, so you'll have to play around with the detail bias (in the hair shader, not in the shadow map).

 

Another problem is that I don't really have a way to add some intrinsic randomness to the hair coloring, like the default hair shader does with it's two tip colors. If someone here knows how I can get something like a unique hair id that stays constant through animations, I'll be able to add that in, too (mutant hairs, for example).

 

Ciao, Daniel!

 

2007/2/27, Marc-Andre Carbonneau <marc-andre.carbonneau(at)ubisoft.com>:

Hey Daniel,

 

Perhaps your shader is already good enough but I lack the ability to make it look the way I need?

 

I am trying to make "dry" hair. Attached is an example.

 

What happens is that I get specular that is too harsh and all over the hair. If you look at the image, you notice how it's really uneven.

 

I notice that the Muhair shader requires a light setup that is different than the one I use for my face…otherwise the colors are blown?

The volumic shadow maps don't seem to work either. Is this a bug?(might be because Muhair was developed a while ago?)

 

I just did some test with a little comping and I'm getting closer but that's with the Hair_geo_shader which takes long to render.

That's why I'd prefer to use Muhair.

 

Thanks

MAC

 

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From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM] On Behalf Of Daniel Rind
Sent: February 27, 2007 10:14 AM
To: XSI(at)Softimage.COM
Subject: Re: Shading hair

 

Well, post your wishes.

 

Ciao, Daniel!

 

2007/2/27, Alan Jones <skyphyr(at)gmail.com >:

I've messed around with a sprite shader with a mixer gradient using
the bary co-ordinates to drive the matte and using OrenNayaWolff for
the illumination and got some reasonable results - though it was a
long time ago. (Sorry for pimping my own warez)

Cheers,

Alan.

On 2/27/07, Kris Rivel < krisrivel(at)gmail.com> wrote:
>
>  Let this be a reminder how badly we need some better hair shaders and
> better hair control overall.
>
>
>
> Kris Rivel
>  3D Artist
>  kris(at)krisrivel.com
>   www.krisrivel.com
>
>
>  Marc-Andre Carbonneau wrote:
>
>
>
> Hi.
>
>
>
> I have a full head of hair to shade. It needs to be realistic. I'm using
> Muhair and I can't get something that looks convincing.
>
> I've been told it's way better and faster than XSI's hair shader and the
> hair_geo_shader.
>
>
>
> My character has short blondish hair that looks dry.
>
>
>
> Anybody got something real looking and could provide me with indications,
> light setup, shader tricks?
>
>
>
> We made hair before but it didn't have to look realistic so to speak…
>
>
>
> Thanks.
>
>
>
> MAC
>
>

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