in some tutorial ,hair has anistropic material,but in some is nothing.

should hair be anistropics in material

and reflection and speclur be all right?

In my opinion, none of the Poser shader abilities are "correct" for hair. I know how to do numerous things well, with a shader that works in 99.99% of situations, for many materials - but not hair.

This is an area where a "physics based" shader just cannot be built for Poser, using only the nodes they give us at this time. (Future readers - perhaps this statement is not true - so pay attention to the date and version. I'm talking at a time where Poser Pro 2014 is the most advanced we have. I know nothing at all about future versions.)

So - what are we to do? Give up?

Well, no, but this is a situation where I can only provide guidance. The details will be coming from you, and will be in response to the textures you're given, the hair you're working with, and the lights you're using.

Ready?

Yes - your best option for hair highlights is with the anisotropic node. But it needs help and you need two of them. 

You need two because hair produces a double highlight. 

You need to help it because this node produces incorrect results at the "crown" - the very top of the head.

You should realize also that the anisotropic node is a poor simulation for light and only reacts to Poser lights, not to Poser scenery. It will not at all react to the sky, so it will not look right just with anisotropic nodes.

It will also be strongly disturbed by discontinuities in the mesh normals, so if your hair has few polygons, use subdivision to make the hair polygons bend really smoothly.

Here is a setup for the primary highlight. This has the color map going into an HSV node. Use the HSV node to desaturate the diffuse color (saturation < 1), making it closer to a shader of gray. Increase the value (value > 1) to compensate for a dark color in your color map.

For this color map I used saturation = .5, value = 2. You will have to use your judgement about what values to use.

The anisotropic node is set up with highlight sizes in u and v (.5 and .05). This produces a narrow highlight across many hairs.

The EdgeBlend node is there because the anisotropic node sometimes makes an extraordinary (and wrong) bright highlight at the top of the head - we want to prevent that.

Here is a render of just the primary highlight.

This may be just my ignorance ... but couldn't reflection be tweaked to work with both stran based and trans-mapped hair?  I'm sure it isn't the most accurate ... but couldn't it be more useful than anistropic?

Now for the secondary highlight, we can only sort of do the right thing. The secondary highlight is shifted and color intensified - it is caused by the hair shape, which is covered in slanted scales, as well as internal reflections and refractions, which transport the light away from where it entered. We cannot do this effect in Poser. If I could supply a normal map value for each anisotropic node by itself, I could do it better - but they (SM) didn't think of that - so no.

So I do this - which is better than nothing. I make another color from HSV of the color map - this time I'm increasing saturation and brightness. For brown hair you want to find a nicely matched gold color. For black it should be closer to gray or even blue. You can tint a bit using the color chip as well - although I did not have to here. I raised the Value to 10 so it is nice and bright.

The V highlight size is bigger here in the anisotropic node. This makes the band of highlight wider.

This may be just my ignorance ... but couldn't reflection be tweaked to work with both stran based and trans-mapped hair?  I'm sure it isn't the most accurate ... but couldn't it be more useful than anistropic?

Strand-based hair is not a 3D object at all - it's a collection of tiny 2D billboards, rotated so they always face the camera. They're not round. They don't reflect correctly no matter what you do. As for reflection on transmapped hair - it can look decent, but takes ages (literally days) to render.

Here's a render of the secondary highlight alone.

Thanks for the clarification.  That makes sense to me now.  This is coming along fantastic!

Here is how to combine the two highlights. You use a Color_Math:Add to add them together (I use matmatic to generate these - matmatic called it Color_Add). The two anisotropic nodes can share the color map and edge blend, but each must have its own HSV so that they use different colors.

Here is a render of both primary and secondary highlight. I hope you can see from this what a dramatic improvement it is to make the double highlight.

Note - I am using the Alternate_Diffuse for my specular. This is on purpose. I know what I'm doing. Trust me. It matters but isn't worth explaining. Just do as I do.

Finally, connect your diffuse color (in my case - it's just a texture map) into the Diffuse_Color as usual. Adjust the brightness using the Diffuse_Value - I usually start with .8 and go from there.

The final shader renders like this.

is just what I wanted for hair!  tried using fine displacement to sim. strand-based appearance but couldn't get it to render well.

As you use different color textures, you'll need to use your judgement about adjusting the HSV values. But now that you know what to look for, you should be able to figure it out.

For this darker, redder texture, I doubled my values - the primary highlight HSV Value is 4, the secondary highlight HSV Value is 20.

By the way - I'm not actually using different color maps. I am manipulating the same map with nodes - I'm able to produce an infinite variety of colors pretty easily.

The most useful single-node manipulation is the Color_Math:Bias node - connect your color map to Value_1 and then try different solid colors in Value_2. Following that is HSV. If you plug your color map into these types of nodes (or both in series) you can create an incredible variety of color maps on the fly.

Cool. This seems a little different than your vss anisotropic with edge blend shader. I got some good results with that shader in combination with a texture map without burned in specular.

thanks a lot

As always, this is excellent material.  Thanks BB.  Have you ever considered writing a book?  I'd certainly buy it. 

As always, this is excellent material.  Thanks BB.  Have you ever considered writing a book?  I'd certainly buy it. 

I've nagged him about it, and even bought a couple of whips...but he ignores me :)

Is it better to use diffuse or scatter for the "diffuse" part? Or both?

I ended up using this hair shader here: https://www.renderosity.com/mod/gallery/healing/2743787/?p I feel it really helped pull it together

For future reference on hair shaders check out this thread at SM: Here

Boni posted at 7:45AM Wed, 24 May 2017 - #4305748

For future reference on hair shaders check out this thread at SM: Here

That was how I found this one :) I couldn't get some of the other shaders/effects to look right in SF