I have been working on my own personal skin shader for a while now, enough time that I am starting to get glossed eyes when I look at it, so I thought it is time for some external feedback.

I have done a render with the default skin that comes with the Elena character, as far as I can tell, it is based on EZSkin SSS.

Firstly, here is a render with a blank white mat on V4 so you can see the lighting

While I do like the look of my material more, I would like to remove more of the dry skin look and also soften the lips up.

There is also a bit of an issue with the bump mapping, specifically around the brow and lips that give a very hard look to the surface.

Any feedback, thoughts or comments to help me improve my skin shader would be great.  Be friggin brutal, I can take it!

Your best bet might be to make an SSS map, if you haven't done it already so you can control the amount of SSS in the areas that you want.

Laurie

at the moment I use a combination of component, bias and blender to turn the diffuse map into an SSS colour map.  if further tweaking doesnt help with the dryness, I will give a custom texture a go.  I have a tablet with a pen so that shouldnt be too hard!

Does anyone know what the proper colours should be (averaged of course) for pre scatter and scatter colour?  maybe Im attempting to make the wrong colour tone

I am using custom scatter as I find it to be much more configurable that the subsurface skin node.  As a result I have been able to blend between the SSS on the skin, and a more standard diffuse for the eyebrows and makeup with smooth blending.  it also allows node based control of the travel distance which has allowed me to make more realistic SSS accross the different areas of the face.

I think your skin is looking pretty good, certainly better than the default.

I'd be interested in your settings on the custom scatter node.

Thanks CaptainMARC.   If my computer comes online while I am at work, I will take a screenshot of the material, otherwise I will get it for you when I get home in about 8 hours or so.

That'd be great - but no hurry!

On further reflection some thoughts:

regarding dry skin and bump issues: could be the same thing. In general the bump may be a little heavy, and I'm not talking about reducing it, but softening it;

I can understand your issue with the lips, but some lipsticks do look like that, so purely a matter of taste;

another point: eyes! They look a bit dead, what about some reflections?

Finally, something you didn't ask about, but the only other thing in the render that catches my eye, hair! It looks a little too uniform, it should sparkle and sheen a little. Don't ask me how. I only use transmapped hair for background figures and I have enough problems getting strand hair to behave haha!

The shader that is in use on the hair at the moment is an experimental one I created for use on trans-mapped hair to make it look like strand based hair.  It still need a fair bit of tweaking, but (unless i mis-understood you) the fact that you thought it was strand hair means I am going in the right direction!

Tonight I am actually going to attempt to use two custom scatter nodes to create more realistic multipole SSS material in the hopes that this will give me a softer looking skin without having to sacrific texture detail to do so.

The eyes (in my render) do actually use real reflections, its just that there is not a full scene surrounding her to create reflections.  Check out the attached image, while the skin shader is different, the eye materials are the same (well the iris is a different color). I think it still needs work, but they look much better in this render (it has a full city surrounding her)

Thanks for all the feedback!

My computer wont come back online while im at work, and I have a few ideas to change my skin shader, so I will write them here so I dont forget!!

Multi-Layer Skin

Dermis - Custom Scatter

use diffuse texture for prescatter color

use diffuse texture red component through blur node setup for scatter color

mean path ~ 3

Epidermis - Custom Scatter

use Dermis custom scatter node as prescatter color
Use blur node setup on diffuse texture - red component for scatter color

mean path ~ 10

Diffuse -  Clay Node

use diffuse texture for color
use blur node setup with bump texture for roughness

Are there many / any skin texture products in the marketplace (or freebies) that include (or just are) an SSS control map already?

I guess a good SSS map is based on body topology (e.g. ears or fingers may want more?)... would that be right?

How specific would an SSS control map be to the diffuse / specular / bump (etc) maps?

Attached is a composite of my first multi-layer SSS material for poser.  I absolutely love it so far, and there is much tweaking to go!
Single light source with indirect lighting, final render settings

Dermal is custom_scatter with the pre_scatter colour coming from a color_ramp controlled by a desaturated diffuse map. Scatter colour is a deep red orange
mean_distance = 15

Epidermal is custom_scatter with pre_scatter colour coming from a hue shifted desaturated diffuse map. Scatter colour is a pale blue
mean_distance = 4

Diffuse is clay with colour coming from a slightly desaturated diffuse map
Roughness is controlled by an desaturated diffuse map

Epidermal is added to Dermal then clamped.  The Diffuse is then added to the result and then clamped again.

Specular is a combination of microfacet controlled by specular map and diffuse map for roughness, finished off with a specular node controlled by the specular map and the bump map for roughness.   These are added and then clamped

this is a 340mb HDRI IBL map with matching specular light of a large open urban park on a clear sunny day.

Not meaning to be caustic, but I don't really know how to guage what you're showing us here.

I have this difficulty a lot in the Poser sphere because people are looking to achieve such varying results, from photo-realism to faux illustration.

In terms of the latter, I can't comment meaningfully.

In terms of a photo-realistic skin, it's still hard as the context (placement in a scene) is quite vague, but I'm tending to find the appearance of your shader quite flat (particularly in the last two renders), lacking in a specular/reflection response (maybe because of context with reflection on the skin) and not demonstrating much if any SSS. Perhaps this is partly due to the diffuse/control maps requiring more variation in colour & tone.

I do like the approach of breaking down the layers and control maps to something like a RW structure, something I'd like to play with more if I had the time and the tools (I really need a direct 3d painting tool which I dont have at present).

Really love what you've done with the transmapped hair - yes, very like DH in appearance.

Just wanted to add, I've been exploring skin and scatter nodes etc using the Lee-Perry-smith model rather than any of the figures at present, comparing variations in shaders under the same sets of lights (several presets) and set in an EnvironmentSphere scene (varying HDRs).

I would second this. The Lee Pery smith model is a great testbed for building nice looking skin shaders in whatever app you use. It's much better then any poser model cause it's built from a scanned human face and comes with high quality displacement and diffuse maps. If you can get it to render nice in your renderer, you can be sure that your shaders are good and any further tweaking should be done on your poser textures/mesh, not the shader or lighting. You can also compare your render with those from other apps to get an idea of how good your results are.

The hair shader looks great, I'd love to see more examples of that!

Carodan,   Thankyou for the feedback.  Firstly, what is the Lee-Perry-smith model?  Do you have a link to the stuff I need to replicate this?  I assume this is like the cornell box for GI rendering?

Really all I am wanting to do is end up with a shader that I personally like the most. I find EZSkin looks entirely too waxy and fake, RealSkinShader is pretty good, but the renders look too plasticy in many lighting conditions.  I love playing in the material room, its almost all I do in poser (that and cloth sims) so I figured this would be fun to try!!

As for your comment regarding flatness,  can you explain a little more?  Do you mean the shading of the skin between bright and dark areas is lacking in contrast, or do you mean the level of colouring in the skin is too uniform?

This weekend I am going to try and replace the Dermal pre_scatter node setup with an image I create myself using my Tablet. Im no anatomy expert so I may can that idea pretty quick :P

With regards to lack of SSS visibility I totally agree that its hard to see.  I kind of get foggy eyes when working on shaders, as I render so many times you start to see things much easier than someone just looking at one image.  Ill make some changes and see what comes out!

Oh, thanks for the feedback about the hair too!  I improved it a heap last night!

JohnDoe641,  I will post a screeny of the material shortly, providing I can connect to my home PC from work

CaptainMarc, I will get you that shader today too!  sorry for the delay, got uh.. sidetracked last night :P

Attached Link: Lee Perry Smith 3d head resource

i just find it a useful resource as the geometry & maps give such a solid base to aim at realism, given that it's derived from a 3d head scan.

Thanks heaps for the link!   I have seen this head a few times before, but had no idea where it came from.   I will apply my shader to this tonight and do some rendering

I havent played much with the layering you're using here, but I'd have a guess that what is needed might be some variation in the tone & colour of your dermal map, combined with a good SSS control map. What that would look like i have no idea. That and a little more modulated specular & reflection (again, a map is really needed here).

I actually quite like some of the waxiness we get with EZskin and think its not unrealistic. What often lets it down IMO is often the underlying model and the maps used.

We cant forget that skin is likely to look quite different under different lighting conditions. Yesterday I was looking a my partner's skin in shadow outside on a very bright sunlit day, and it was remarkably transluscent in places. Under the light in our front room tonight and with a tablet screen quite close to her face, she doesn't seem that far from your second to last render, but with more specular/reflection. 

that looks quite impressive so perhaps EZSkin was let down by the textures when I played with it.

I thought perhaps using a multiply and bias node on the pre_scatter of the dermal layer to add better colour variation to the end-result texture it uses.

I have such problems with my internet at home.  I use teamview to access my home PC from work, but for the past 2 days, it has been dropping the wifi connection in the 15 minutes it takes me to walk to work. SO ANNOYING!

Im watching Question Time on TV here in the UK (politics panel programme with a strong interation with the audience) and the variation in how the studio lighting falls over different faces in the audience is amazing. You can really see the fact that many of the women are wearing foundation makeup, an extra layer that interferes with translucency & shine & variation of colour. Many more of the male faces are much more ruddy & shiny. Theres a rich blue/red gradient backdrop behind the panel that's reflecting a lot of colour into the shadows on faces from certain angles. 

It's an interesting study.

I often find myself staring at people in the city for this very same reason LOL.

The HSV next to the diffuse map is just to change the colour of the hair to more match my characters eye browse.  it is not required if your texture is already the right colour

Sorry its not lit from the same angle, I didnt save that file last night

Firstly, I used really quite a low scatter scale of 1. We've been leaning toward 1.6-2.0 lately to avoid that waxy look, but I'm not sure this hasn't made for an overly dry or flat looking skin. The other effect of lowering the scatter scale is that it helps soften the shading at the terminator between light and shadow, and seems to help soften the bump sharpness also.

The other major change I made was to the blin node, increasing the default EZskin eccentricity setting to 3.3. My Spec rolloff is 3.5 (I can't remember if this is the default or not). I think this re-introduces a little solidity to the surface appearance of the skin in the brightest areas.

I also used a texture detail setting on the scatter nodes of 0.7.

Quite important here is that this was quite a high res render with high quality settings on (shaders) reflection, scatter, (render) IDL, pixel samples, shading rate etc. Also, I employed the bb suggestion of lowering IDL intensity in render settings (0.5) to avoid too much diffuse glow. It did take a couple of hours to render, so this might be pushing things for many who are looking for quick results, especially when you start adding more elements like hair, clothes etc.

Thing is, this setup isn't neccessarily going to work for all lighting conditions. Remove specular from the RT light and use IDL only with reflection based specular and this will look pretty awful. I think scatter, lights and render options really need a few more options in order that we can seperate out & adjust some of the shading responses. EZskin as a base for most lighting conditions is still a pretty good option though IMO.

Quote - I increased the intensity of the dermal layer composition with the epidermal to increase the SSS effect.  I also increased the specular intensity by about 50%

Sorry its not lit from the same angle, I didnt save that file last night

Yes, you can see the added SSS and specular. She's entering into that 'waxy' look. I wonder now if you slightly change the specular (see my last post). If you're using Blinn, try increasing the Eccentricity and see what you get. Try the lower IDL intensity trick (via the D3D render dialogue) as well (helps with the diffuse shading).

In low lighting settings like these it's naturally harder I think to see variations in diffuse, so it's possibly less of an issue, but I like it that there's an increased reddness. What you do lose is the variation in shading from the upper skin layers to the underlying dermal layer. It's this transition that I find most difficult to achieve.

Added a RT Spot back-light. so we can see the SSS on the ear.

This time I rendered with an even lower IDL intensity of 0.3 (bb suggested as low as 0.1 to eradicate over-glowing diffuse). This render option is ever more important to me at the moment with regard to skin as the shading seems so much better to my eyes.

I'll give this setup a go on V4, but in the past she's not looked half as nice as the LPS model. Might be good for direct comparison to your shader. The maps are possibly the problem in my case.

So, I realised a mistake on my part regarding scatter scale. Using the LPS model I forgot I'd imported it way bigger than a typical Poser figure, so the scatter scale I was using was going to need to be a lot less than normally.

Just disregard that lowering scatter scale business. The EZskin defaults are about right.

Sorry about that.

This render shows that there is too much ambient build up from the multiple layers. It also looks too plastic-ish.

Im going to use what I learned on this shader to make a new one, using LPS instead of V4

9 minutes to render what you see

It's an interesting exercise using LPS. Yes, the ambient looks too high.

It is a little tricky not having a full range of maps for him. That's why I quite like EZskin with it's procedural options, although that isn't ideal either.

It's quite an eye-opener when you see just how simple LPS's base mesh is though, and how the normal map adds in all that detail (I keep forgetting to apply the displacement, but he renders nicely without). I find it very useful to be able to identify the part that mesh plays as opposed to shading & mapping.

Poser's SSS algorithm needs no elaborate map setup. It can gather all information needed from the color map and the geometrical shape of the object it is applied to.

Here is LPS using the slightly tweaked EZSkin shader I use for all my models.

IDL at full strenght plus a single infinite light at 40%.

And yes, I'm saying this for years: Most of the realism lies in the correct shape of an object. So putting a photorealistic skin shader on your typical stylized Poser mesh makes perhaps for a prettier render, but definitely not a more realistic.

The typical outcome is usually something like this:

http://pixeloo.blogspot.de/2008/03/homer-simpson-untooned.html

and this

http://pixeloo.blogspot.de/2008/04/jessica-rabbit-untooned.html

....although not quite as entertaining.

;-)

JoePublic - agreed, underlying mesh shape is so important.

You'd probably have a good idea on this. Do you know of any apps for deriving shapes that can be used to create a morph for, say V4, from a series of photos of a subject?

I tried a plugin for Poser & DS a few years ago (cant remember its name now) but it fell way short of expectations.

Well, I usually do my morphing the hard way, dial spinning, lots of magnets and ZBrush. I also put more emphasize on correct body proportions and shapes than exact likenesses.

:-)

For Poser there is Faceshop and FaceGen, but I never really bothered much with those after seeing Volker Blanz incredible technology back in 2007:

http://www.youtube.com/watch?v=nice6NYb_WA

It looks like that tech is finally available for the masses:

http://www.vizago.ch/

Transferring a shape from a new head object over to the V4 mesh shouldn't be a big problem with the morph/shape transfer utilities available.

I also had good success using the ZBrush' projection brush transferring shapes. I used it to make a "V3" clone out of V4 and a "V4" clone out of V3 to transfer morphs between them even more exactly.

this is my next attempt. I need to tone down the SSS of the dermal layer and reduce the diffuse layer a little

--edit--

oh there is no specular at the moment

Templar.

Great thread! I am too tired to comment in depth-but I'm not sure the Elena SSS is default EZ Skin. Also-there is a LOT of room for change with EZ skin-it is not really a set look.

More later after SLEEP.

Depending on what setup you use with EZskin (or custom shaders) then the maps are going to be driving many of the surface responses. Using a single texture like the diffuse map to drive everything just isnt a good idea and you quickly recognise the sheer diversity of textures out there, many of which really arn't suitable for use with scatter. I've made many adjustments to diffuse maps to get them looking better with scatter, from cloning out shine to completely changing hue/saturation/lightness and making blends with other character textures.

You can get away with a lot though, and i'm kinda with JoePublic in that the underlying mesh shapes are often what is falling short (in terms of achieving realistic human renders).

templargfx - your LPS renders are looking good. Are you also doing quick tests with other lighting states?

Quote - ok, here is a render using just a custome scatter node for sss.  I did not know that surface colour has a huge effect on skin softness

Skin softness is one of those things i try to acheive, and its really tough to find that sweet spot, particularly in certain lighting states. Most of the time for me its what happens at the terminator that disturbs me - that sudden transition from light to shadow on the side of the head for example. Some of this is about having a good subtle surface bump, but the right amount of translucency can also help achieve that softness (without it glowing red). When bb first suggested an issue with diffuse response to lighting in Poser I was thinking that this might also be part of the problem, as well as relying on lights casting out rays from a single point. 

Those harsh transitions are an issue for me though, particularly when using gamma at 2.2 (i tend to render at 1.8 or 2.0 at present which helps).

Completely agree.

That's why all my (caucasian) characters use the same skin texture. With some slight modification for age and gender, of course. It's the most neutral I could find without being so sanitized as to look boring, and I think it works quite well with EZSkin.

IMO a lot of Poser skin textures look quite strange and only work well with the exact same light, shaders and sometimes version of Poser the vendor who made them, used.

So I rather stick with one that works and modify it myself when needed and mostly rely on different shapes for variety.

Left image is 1 spot light + light emitting env sphere (124mb .HDR map)
right image is the same spotlight but with the environment sphere turned off

IDL on with 8 bounces 400 samples and pixel samples at 6

Changing over to these textures required no changes of the SSS at all, which is a good indication the settings are on target.  I lowered the intensity of the SSS slightly after the last render.

 I'm impressed! I never got custom scatter to work well. Please show your node set up!

Quote - wierd light angel.   This shows the SSS being overdone

Instead, use the following nodes to modify how it looks :

Color_Math - Controls how much strength the Dermal and Epidermal layer has.  If you want dermal to be less visible, and have already dropped this node to 128,128,128, instead reduce the mean_free_path of Custom_scatter to 0.15 and set this back to 200,200,200.

Custom_scatter = Dermal Layer

Custom_scatter3 = Epidermal Layer

Blinn = Diffuse Layer

ks_Microfacet = Specular Layer

You will notice I have 3 textured.  Image_Map_3 is a custom image I made using photoshop that is white where skin is, and black where hair is (eye brows and stubble)  this controls a blending node that blends between a standard diffuse shader, and the MSS skin shader.  You can use a bias math node instead, attach the diffuse to both parameters, and set paramater 1 to 1.000 and paramater 2 to about 7.000  increase or decrease the second parameter to find the sweet spot.

I have used this shader now on 5 different V4 characters, and they all not only render nicely, but have required only the slight adjustment of the bump mapping and no touching of the SSS nodes at all.  This really suprised me, as I thought I would be tweaking the crap out of each SSS node every time the base diffuse map changed.

Thanks!

I'll play with it a bit!