This is part 2 of the Making Skin Pop with the Daz Studio Iray Uber Shader tutorial. Here, we address tweaking a chromatic skin. Part 1 provides an introduction to Daz Studio Iray skin shaders as well as how to convert monochromatic to chromatic skin. Visit Part 1 here.

Tweaking a Chromatic Skin

1. Open up a figure of your choice (I’m using Babina 8 for my example) in Daz Studio.
2. Open up the Surfaces tab.
3. You’ll notice that the SSS map slotted into the Translucency Color looks different this time – it would normally either be an exact copy of the Base Color map, or a lightened version of the Base Color map. (It is important to note that some skins might have a more in-depth SSS map that incorporates things like veins and vessels, but the vast majority are simple lightened versions of the Base Color map.) In the case of Babina 8, you will see the latter, a lightened version of the Base Color map.
4. (Optional) If the skin you are working with uses a copy of the Base Color map slotted into the Translucency Color, I would recommend lightening it slightly in Photoshop. For a generalized process, start with the color map and add a Hue/Saturation Adjustment layer with the following settings – Hue -5, Saturation -15, Lightness +20. This might need to be tweaked depending on the skin. Once you have a lightened version of the color map, load this new SSS map into the Translucency Color slot and move to the next step.
5. Change the Translucency Weight to .90 (you might need to play with this depending on the character).
6. Change the Base Color Effect to Scatter & Transmit Intensity.
7. Change the SSS Reflectance Tint to 0.79, 1.00, 1.00. (you might need to play with this depending on the character, but I like this color almost all the time).
8. Scroll down on the Surfaces pane.
9. Change the Transmitted Measurement Distance to .15 (you might need to play with this depending on the character).
10. Change the Transmitted Color to 0.95, 0.20, 0.10 (you can definitely play with this depending on the character and skin tone you’re going for).
11. Change the Scattering Measurement Distance to .015 (you can play with this setting too).
12. Change the SSS Color to 0.95, 0.45, 0.55 (you can play with this setting too. In fact, you will have to depending on the character and look you’re going for).
13. Change the SSS Direction to -.25 (I typically don’t mess with this and leave it set to 0, but using small negative values, such as -.1 to -.25, can be helpful if there is too much scattering effect. This can vary greatly on lighting).
14. Repeat these steps for the Lips and Ears (I often do them at the same time as the Face since they use the same maps).
15. Repeat these steps for the rest of the skin surfaces – Arms, Body, Legs, Fingernails, Toenails, EyeSocket, etc.

Again, play around with the settings! That’s how you’ll learn what you like and dislike and what different colors and numbers do. This is where you might think about tweaking the settings for Bump, Top Coat, and/or Gloss/Specularity. They all add up to the skin’s final results! And if you’re comfortable with Photoshop, you can even build upon the SSS map for more detail (blending tattoos into this layer can help immensely in making them look more realistic and less stickerific). Also note that I do not adjust eyes…you can easily slot in eyes from another character.

It looks like a lot of steps, but it’s really not when you get in the groove. It also really helps to save your go-to colors to the quick select in Daz. Please see the below comparison for Babina 8.

Middle face skin was made following the steps above. Far right face skin has changes to Transmitted Color and SSS Color to create a lighter skin tone.

And just like with above, these steps work with darker skin tones, as shown below with Millawa 8, who has gorgeous skin out the box to begin with. My first tweaks are very subtle, but upon close inspection you can see that changing the Base Color Effect to Scatter & Transmit Intensity enhances the toning of the skin (in this case I used a color of 0.37, 0.99, 1.00 which seems really bright but it’s subtle with Millawa’s skin maps).

Comparison of out-of-the-box Millawa 8 skin with multiple tweaked Millawa 8 skins.

And lastly, we have Celani 8, another character with gorgeous skin out of the box. I changed the Base Color Effect and altered the Transmitted Color and SSS Color slightly, and the effect is very subtle. I also included a shot with her under different lighting so you can see how lighting itself has a huge effect on the same skin and settings.

Comparison of out-of-the-box Celani 8 skin with tweaked Celani 8 skin in normal and altered lighting.

In conclusion, the best advice I can give is to not rely on using things out of the box. Don’t be afraid to roll up your sleeves and dig around in the surfaces panel. Play around with stuff to see what it does. What’s the worst that could happen if you end up with something you don’t like…just undo or reload! I hope this guide and these steps help get you started on achieving the results you want when it comes to the way skin looks, whether you’re a beginner or a grizzled veteran trying to get used to Iray for the first time. In time my goal is to write more tutorials in the future that take these steps even further and build upon them. Happy Rendering!

Have you ever been frustrated with skin that looks flat in Daz Studio? Dull and lifeless? Rubbery with a distinct likeness to that of Gumby? (Google it if you’re too young to remember Gumby.) Or maybe it just needs a little bit of pop? Most of the time, any of these issues can be attributed to SSS, or subsurface scattering, and there are a couple easy tweaks that can be made to drastically improve the look of skin in Daz.

[Visit Part 2 of the tutorial which deals with Tweaking a Chromatic Skin.]

PBR Skin Shader vs Iray User Shader

Before we get started, I wanted to make a quick note regarding the new skin shader that was introduced with Genesis 8.1, the PBR Skin Shader (it can also be used on Genesis 8). ‘PBR’ is actually a technical term.

Physically Based Rendering, according to Wikipedia, is ‘a computer graphics approach that seeks to render images in a way that models the flow of light in the real world.’

Okay, well that was kinda vague. Both the PBR Skin Shader and the Uber Shader do this, so they are both technically PBR shaders. They use almost all of the same maps. So please don’t let Daz’s play at words lead you to believe that the Uber Shader is somehow lesser. It’s just different. While the PBR Shader has added a couple neat new tricks, it is also missing some neat tricks that will be made use of in this guide. Essentially, the PBR Skin Shader is a trade-off, and it’s up to the user to decide which they prefer. Please see the below comparison with Victoria 8.1.

Victoria 8.1 comparison of Daz Studio’s PBR Iray Skin Shader and the Iray Uber Shader.

It is so very much personal preference. Personally, I stick with the Uber Shader because it allows me to better control SSS. Now, if Daz were to update the PBR Shader to bring back the SSS capabilities that the Uber Shader gave us, then it would be the best of both worlds. But for the sake of this article, I will be sticking with the Uber Shader. (Another article may come at a later date that works specifically with the new Iray PBR Skin Shader.)

Spectral Rendering

One other item of note is Spectral Rendering. A lot of folks don’t know what it is and a lot of folks don’t use it. Personally, I do, and I don’t. It depends on the scene and the skin I’m working with. It is supposed to be more actuate in terms of how it bounces light around the objects in the scene, some scenes more than others. The downside is that it has a particular tendency to make skin out of the box look like muddy, green, flat…blech. The tweaks I will be going over won’t work with Spectral Rendering. Well, they will…but they require different SSS settings to not look like muddy, green, flat…blech. It also can add exponentially to your render times, even with the same exact lighting.

Is it really worth it? That’s up to you to decide. Like I said, I’ve noticed that Spectral rendering works better with some skins than others. For the purposes of this article, due to length, I will be sticking with basic rendering. If folks enjoy this article, I will do a write-up of my tweaks translated to Spectral Rendering at a later date. For comparison, here is an example with Vicky 8.1 with my Iray Uber settings.

Comparison of Iray Uber Shader with and without spectral rendering.

Okay! Ready to get started? Oh! I forgot to mention that if you want to follow along in Daz, I’m using this HDRI and no other lighting and default tone mapping.

My lighting setup – Just HDRI and no other lighting or default tone mapping.

Monochromatic vs Chromatic Iray Uber Skin

The first step is understanding what type of skin you are starting with, and that really boils down to SSS (subsurface scattering). To put it simply, think of subsurface scattering as the way light shines through the skin. Skin is translucent, so it’s only natural that we’d see things like veins and, well, meat beneath it. Older Iray Uber skins, such as those found on G3 and a very small amount of G2 characters, use a type of SSS called Monochromatic. Newer Iray Uber skins, such as those found on G8 (and G8.1) characters, use a type of SSS called Chromatic.

Now, what is the difference between the two? Well, I honestly couldn’t tell you, other than the fact that they behave completely differently, and that Chromatic SSS, when set up correctly, appears to behave more naturally in terms of light reflection than Monochromatic SSS. So how do you tell which is which? It’s really easy, but you’ll need to roll up your sleeves a bit and open up the surfaces tab (If you’re never looked at the surfaces tab, or are unfamiliar with it, you’ll be digging into it here!):

Monochromatic

You will see a greyscale map slotted into the translucency color. You’ll also see a rather tomato-inspired red set for the color itself (in most cases). And if you scroll down on the surfaces panel, you’ll see the word ‘Mono’ listed under SSS Mode.

Monochromatic skin typically uses a lower translucency weight (.3 to .5) and the general rule of thumb is that it can be lightened or darkened by adjusting that slider (lower for lighter, higher for darker, etc). Monochromatic skin can be converted to Chromatic skin with some work, and that work does involve Photoshop (or another photo editing program that can use layers, such as Gimp). I will be showing you how to convert a Monochromatic skin, such as Vicky 7, over to Chromatic SSS and apply my tweaks. (I’ll try to stick with the super popular base figures that pretty much everybody has so you can follow along exactly.)

Chromatic

You will likely see either an exact duplicate of the base color map slotted into the translucency color, or a slightly lightened version of the base color map. The translucency color itself should (in most cases) be white (this isn’t always the case for spectral rendering, but again, this article will only cover basic rendering). And if you scroll down on the surfaces panel, you’ll see the word ‘Chromatic’ listed under SSS Mode.

Chromatic skin typically uses a much higher translucency weight (.75 or higher) and it is harder to lighten or darken simply by adjusting. This can be tweaked slightly, but if you need to lighten or darken a skin drastically, I would recommend finding a different skin that starts out where you want it in terms of tone, or go the direct route of editing the maps manually in Photoshop (advanced users). The reason for this is that Chromatic skin relies on the translucency color map, or the ‘meat map’ as I call it, to shine through from beneath the outer base color layer. If you try to lighten the skin by dropping the translucency weight, you’ll lose that ‘meat’ and the skin will end up looking flat. Chromatic skins out of the box are the easiest to tweak because they already have the necessary SSS map (though advanced users can go even further and build a new SSS map or tweak the existing one for even more detail, something I will cover in another tutorial).

Converting Monochromatic SSS to Chromatic SSS

(Beginner Level in Photoshop Required)

1. Open up a figure of your choice (I’m using Victoria 7 for my example) in Daz Studio.
2. Open up the Surfaces tab.
3. Starting with the Face, open up the translucency map in Photoshop (or photo editing program of your choice that supports layers). In the case of Vicky 7, this map is here on my system – DAZ 3D\My 3D Library\Runtime\Textures\DAZ\Characters\Genesis3\Victoria7\V7FaceMapSSS_1001.jpg. There are other SSS maps for Vicky 7 that are dependent upon any makeup you choose, but for our purposes, we’re only concerned with the base skin that loads with the character. You can always convert the makeup skins if you’d like later (I usually just use third-party makeup anyways).
4. Once you have the Face SSS map open in Photoshop (it should be greyscale with blue squigglies), take a look at the vein detail. It’s great! I really wish Daz kept these details on their newer figures but c’est la vie. Now open up the base color map, in this case V7FaceMapD_1001.jpg. We’re going to need both to create a proper Chromatic SSS map.
5. Next take the SSS map and copy/paste it onto a new layer over the base color map. You should now have two layers…one with the SSS map, and one with the base color map. The SSS map should be on top, currently blocking the color map from showing.
6. Change the opacity of the SSS map to 25%.
7. Now create a new solid color adjustment layer and pick a nice fleshy pink tone (205,165,165).
8. Change the opacity of the solid color adjustment layer to 20%. The pink layer will bring back some nice color to the map we’re building.
9. Go ahead and save this working file as a .psd if you want to come back to it later and play around (I would highly advise playing around…that’s how I learned!). Flatten the image or stamp visible if that’s you’re thing and save this new SSS map as a .jpg (the highest quality setting). You can save it in Vicky 7’s folder, or anywhere you’d like to save it if you want to set aside a special folder for your custom maps. I’ve saved mine as V7FaceMpaD_1001 – CUSTOM SSS.jpg.
10. Back in Daz, change the Translucency Color map to the one you just created. You do this by clicking on the map in the Surfaces tap and then going to Browse when the menu pops up.
11. Change the Translucency Color to white (you can absolutely play with this if you’re going for fantasy skin colors)
12. Change the Translucency Weight to .85 (you might need to play with this depending on the character).
13. Change the Base Color Effect to Scatter & Transmit Intensity (Vicky 7 is already set up that way, but if the character you’re working on doesn’t have it, go ahead and change it).
14. Change the SSS Reflectance Tint to 0.56, 0.98, 1.00. (you might need to play with this depending on the character, I usually start with 0.79, 1.00, 1.00 and adjust from there).
15. Scroll down on the Surfaces pane.
16. Change the SSS Mode to Chromatic.
17. Change the Transmitted Measurement Distance to .15 (you might need to play with this depending on the character).
18. Change the Transmitted Color to 0.95, 0.20, 0.10 (you can definitely play with this depending on the character and skin tone you’re going for…unlike with Monochromatic SSS, this is where you can go to fine tune the ultimate lightness/darkness and tone…to an extent).
19. Change the Scattering Measurement Distance to .015 (you can play with this setting too).
20. Change the SSS Color to 0.95, 0.45, 0.55 (you can play with this setting too…in fact, you will have to depending on the character and look you’re going for).
21. Change the SSS Direction to -.15 (I typically don’t mess with this and leave it set to 0, but using small negative values, such as -.1 to -.25, can be helpful if there is too much scattering effect…this can vary greatly on lighting).
22. Repeat these steps for the Lips and Ears (I often do them at the same time as the Face since they use the same maps).
23. Repeat these steps for the rest of the skin surfaces…Arms, Body, Legs, Fingernails, Toenails, EyeSocket, etc. All of these maps are located in the same folder where we found the Face map (in example, the body would be V7TorsoMapD_1002.jpg for Victoria 7).

Again, play around with the settings! That’s how you’ll learn what you like and dislike and what different colors and numbers do. This is where you might think about tweaking the settings for Bump, Top Coat, and/or Gloss/Specularity. They all add up to the skin’s final results! And if you’re comfortable with Photoshop, you can even build upon the SSS map we created above for more detail (blending tattoos into this layer can help immensely in making them look more realistic and less stickerific). Also note that I do not adjust eyes…you can easily slot in eyes from another character.

I know it looks like a lot of steps but it’s really not so bad, and it goes quickly once you get the hang of it!

Please see the below comparison.

Comparison of out-of-the-box Victoria 7 skin with tweaked Victoria 7 skin.

The above steps can also be followed with darker monochromatic skin tones, as seen below with Monique 7 …the only thing I did different was bump the Translucency Strength up to .90 and change the SSS Reflectance Tint a smidge to give a more golden undertone rather than blue.

Comparison of out-of-the-box Monique 7 skin with tweaked Monique 7 skin.

Visit Part 2 of the tutorial which deals with Tweaking a Chromatic Skin.

Sub-surface scattering (SSS)

In the introduction to this series I explained how Physically Based Render engines work – simulated light bouncing around interacting with surfaces.

SSS is the process that defines –

• How light passes through a translucent object,
• How it interacts with the properties of that object, and
• How it exits the object (at a different point – hence scattered).

In practical terms, particularly with skin, it is the effect where you see light pass through extremities like the ear, producing a reddening glow.

Showing Sub-surface scattering (SSS) effects as it passes through the ear, producing a reddening glow.

That is about as far as I can take the science, so let’s look at how SSS is controlled within Octane.  SSS is applied to a material node using a scattering node, which can be applied to both diffuse and specular materials (but not glossy ones).  If you look at the skin shader material in our previous skin tutorial, you will see there is a scattering node attached to all four material nodes (3 scattering nodes, as one is shared between two specular nodes).

Node-graph diagram of our skin shader showing the a scattering node attached to a material node.

The diagram below shows the three scattering nodes controlling (from left to right) the skin’s deep/mid layer, the mid-layer and the surface layer.

Settings for three scattering nodes controlling (from left to right) the skin’s deep/mid layer, the mid-layer and the surface layer.

Octane Scattering Node Settings

1. Density

Density controls how fast light travels through an object, the higher the value the faster it travels (a value of 0 would result in no scattering).  My interpretation of this is that the higher the value, the deeper light can penetrate a surface.  When using other materials, particularly those from the online database, I have found this setting to be very low.  It is very dependent on the size of the model, and therefore the scale used within Daz.  Normally these materials have been developed for use within other 3d applications with a different scaling system, which is why they tend to be set lower.

2. Absorption

The scattered light will be the opposite of the absorption colour.

This setting defines which light is absorbed faster, in the case of the 3^rd node it’s a green/blue.  It took me a while to get my head round this, but essentially the effect is the scattered light will be the opposite of this colour (from a wavelength perspective).  The image shown here is from the colour picker within octane – a colour set to absorb blue will scatter as red.

3. Scattering

Scattering is similar to absorption, but defines the speed at which light will be scattered when it passes through an object.

4. Phase/direction

This controls the direction the light is scattered:

• 0 – light scattered the same amount in any direction
• 1.0 – more light continues to travel in the direction it was originally traveling
• -1.0 – light backscatters in the direction it came from

5. Adjusting the scattering nodes

Sadly there is no one definitive setting that will work across all objects. It very much depends on scale, lighting, position, kernel settings and so on.  It is very much a case of trial and error, and an area I still need to work on.

Practically, you may not need to worry about this setting too much, for example if the object is distant or if the ears are covered.  But if you do need to, it’s a juggling act between getting the right amount of scattering across all skin materials. 

Light wouldn’t scatter like that through a hand.

Note – any changes you make to one material (e.g. ears) will have to be adjusted in other skin materials (e.g. arms), otherwise the change will be visible in the UV seams.  Consider the girl with the red ear above – she was one of my first attempts at SSS.  Now look at her hand …

Light wouldn’t scatter like that through a hand.  As a result I tend to pose a model with the hand next to the ear, and then adjust the density (starting with the deep scatter node).  Density (from left to right) 1, 250, 500.

I tend to pose a model with the hand next to the ear, and then adjust the density. Density (from left to right) 1, 250, 500.

Glossiness

The last area I would like to cover regarding the skin material is gloss/reflection.  This is for subtle gloss effect, so you wouldn’t use this for a wet skin look, but more for areas like the lips, nails, lacrimals, or eye socket. 

Gloss is controlled in Octane using the Roughness setting in both specular and glossy nodes, but is not available in diffuse nodes.  The scale between 0 and 1 determines the level – the lower the roughness, the more glossy/reflective the surface.

The lower the roughness, the more glossy/reflective the surface.

Let’s consider a practical example using the lips.  The lips are currently sharing a material with the face and the ears, which is no good as we don’t want a shiny face! 

• Return to the Material tab and select the Lips surface.
• Select the material assigned to the lips and copy as a new material.
• Now apply this new copied material to the lips. It now has its own material that we can edit.

Select the material assigned to the lips and copy as a new material.

You can get away with this with the lips as they have a clearly defined line between the surrounding face surface, so the seam is less obvious.

With the newly assigned lip material selected, open the node viewport.  I have found, surprisingly, that the best place to adjust the roughness for the lips is in the uppermost scattering node (the one for the deep scatter), which to me, sounds counter-intuitive.  The image below shows the lips with roughness set to 500,250 & 0 (top to bottom).

Lips with roughness set to 500,250 & 0 (top to bottom).

Finishing up in Daz

Octane comes with a free online material database containing 100s of organic and non-organic materials.  I used the auto-material function in Octane for the eye-lashes. This feature takes the surface settings from within Daz and tries to convert them into Octane. The results vary, and it struggles with iRay materials (though it is getting better). Within the Material tab, right-click the item and select Create new material > Auto Material.

I used the auto-material function in Octane for the eye-lashes.

The other materials I used in the Mei portrait are:

1. Cornea and Eye Reflection – Clear cornea shader  (Octane database)
2. Eyelashes – Auto-material
3. Iris – RedSpec
4. Pupils – RedSpec
5. Sclera – TonySculptor Sclera (Octane database)
6. Hair (Actual Hair 2) – RedSpec Hair Shader

The RedSpec materials are part of a set purchased from a 3^rd Party.

I used the iRay OOT Hair Shaders for colour and transparency maps.  I sometimes increase the smoothing value within Daz for hair as well.

Mei portrait

I have always had a real dislike of the Tear object around the eye, which is now part of the eye moisture object in Genesis 3 characters.  I remove it in Daz by using the geometry tool.

• Click anywhere on the tear.
• Right-click and do Geometry selection > Select connected.
• With the tear now selected (see image below), you can right click Geometry assignment > Create surface from selected.
• Name it, and then repeat with the other eye.
• I then apply a null-shader (diffuse node with no settings, and opacity set to 0) to the tears, and there you have it, no more tears!

Selecting the tear area on our figure’s eyes.

Summary

So that’s it for Daz Studio, Octane, and skin.  I still have some work to do, in particular on skin reflection, index of refraction, Fresnel effect, falloff textures and more.  I also want to break down the material a bit more and make it more processor efficient.

Having spent so much time on the skin, I also need to work on bringing the standard of my other materials up to scratch. You will notice many of my models don’t smile, simply because I am yet to develop a material I am happy with. Same goes for clothes.

Thank you for visiting my Daz Studio Octane tutorials. Hope you enjoyed them.

This article and all of the images within were created by the very talented Brian Sains. Copyright © Brian Sains. Check out his gallery here.