Hair Question Tweet

[Iceman9]

I need to drive hair color with roots so I'm using the c4d's hair material to do that. The color results are good but I'm not getting good specular/gloss.

Is there a way to overlay an Octane material so that I don't change the color but add shine/gloss?

[bepeg4d]

Hi,
have you tried to augment the IOR value?
Also, the new sheen parameter in 3.08 should be helpful with hair shader.
ciao Beppe

[Iceman9]

Thank you for your reply!

My situation isn't typical. I am doing a Da Vinci character from his middle age years so he has a mix of grey and dark hair. This must be colored using the roots. (If a hair is grey it is grey from root to tip)

C4D's hair material has a feature to handle this, but then I don't know how I can apply an Octane material on top of that.

My color is working great but the hair is flat looking, lacking specular or sheen. I can't currently add an Octane shader at all w/out over writing the grey/dark mix root color.

I can think of 3 possible ways to resolve:
-Does Octane have any nodes that would work for a mix of hair root color...
-Or is there a way I can overlay a material which would only add in some spec or sheen but not change the color?
-Are there any nodes where I can feed in the c4d hair material's color values?

[bepeg4d]

Hi,
in c4doctane, you need to use the Hair mat for defining the geometry of the hair, but the color and material needs to be an Octane material.
The color from root is taken from the base object uvs, so, if you use an Octane noise in the diffuse channel of a Glossy material, you should see the black and white effect from roots.
If you want to have also a gradient from root to top, you need to use a W coordinate node plugged in a Gradient node.
ciao Beppe

[Iceman9]

Hi,
in c4doctane, you need to use the Hair mat for defining the geometry of the hair, but the color and material needs to be an Octane material.
The color from root is taken from the base object uvs, so, if you use an Octane noise in the diffuse channel of a Glossy material, you should see the black and white effect from roots.
If you want to have also a gradient from root to top, you need to use a W coordinate node plugged in a Gradient node.
ciao Beppe

thanks for this info. I'll explore.

[Iceman9]

OK. I'm back. I do see that the color is carried from the root, which is good.

Onto a follow-up question.

It seems to me there are a lot of posts here (and around the web) with designers trying to get more lustrous shiny hair. To me the problem is inherent to hair. The surface of a scalp has hairs going different directions--casting reflections in different ways, which diffuses the light. Hair understandably looks flat.

The best way to approach it, IMO, is to chea.

The c4d hair system employs this cheat. You can apply a "specular" highlight along a hair over top of the root color. (It's a semi-transparent gradient I believe)

Is it possible with nodes and modes to *overlay* a semi-transparent color/gradient along the hair *while also keeping the root color? (W coordinate node plugged in a Gradient node.)

[bepeg4d]

Hi,
Octane has a physical approach, so you can use a specular matetial for mimic the effect you described, or use a mix/blend matetial between glossy and soecular, or in 3.08, with Metal and Specular.
In the new metal material you can work with IOR, sheen, anisotropy, and different reflection models.
You can also find some interesting hair materials in LiveDB from Tonysculpt.
Have a look also at the works from Rikk the Gaijin for some very good examples of specular hair materials.
ciao Beppe

[Phil_RA]

From my experience, I could not get it right physically speaking. I use a specular material, add a medium node, but leave absorption and scattering as white (inverted On) and gray, set the phase function to something like -0.25 if I recall right, and then use the transmission color to give the hair its color. Tweak the medium density setting, and the roughness of the material. Done.

But the reason I say it's wrong is because transmission should be left white, I should be able to get the proper color from the medium node only, but was never able to, since the hair diameter is so small that even if I boost density to 10000 it still looks wrong. I'm guessing Octane would need some hair shader based on some of the research that has been done over the years by Merschner and such. https://www.fxguide.com/featured/pixars ... hner-hair/