UNIVERSAL HUMAN
SKIN SHADER DOCUMENTATION
For instructions on adding the pre-made Face Texture images, see the Face Textures documentation.
By default the shader will render pink until textures have been added to the Image Texture nodes. You can use it without textures by disconnecting the Image Texture nodes from the Skin node.
Appending the Skin Nodes to the Face Rig/Body & Face Rig
Set the Render Engine to Cycles, as the system may hang several times during the process if it is set to EEVEE.
Load the rig into Blender
Append the material from Skin Shader 2.93.blend (File > Append, and navigate to the Skin Shader > Materials > Skin). Append from Skin Shader 2.79.blend if you're using Blender 2.79.
Select the Body mesh and in the Material Properties select the Head material.
Open the Shader Editor and delete the Diffuse BSDF, UV Map and Material Output nodes.
click the "Browse Material to be Linked" button in the header and select "Skin".
Select all the nodes, copy them, reselect the Head material in the header and paste the nodes.
Connect the Wrinkles and UV Map nodes as per the image on the right.
Appending the Skin Nodes to a Base Mesh or Other Object
Append the Skin material (go to File > Append, and navigate to the Skin Shader > Materials directory).
Select the object and in the Materials Properties click the Browse Material to be Linked button, and select Skin.
In the Shader Editor, select the object's UV map in the UV Map node.
Nodes Overview
The Skin node's colour properties are stacked like layers, whereby the Albedo Image overlays a Base Color, which acts as an optional layer covering the base Skin Tone underneath. The Subdermis/Subsurface, Roughness and Displacement are not affected by the layering. The top two inputs are for connecting wrinkle maps, which can be ignored if you're not using the Face Rig or Body & Face Rig.
The Makeup node is separate from the Skin node (since it was tall enough already), and overlays the Skin properties. Although it may appear daunting at first glance, for the most part it's just same three properties duplicated for each of the five makeup masks.
Skin Node Inputs & Properties
Wrinkle Masks & Wrinkle Displacement
Input sockets for the two Wrinkles node outputs.
Albedo Mix
The Albedo image opacity. Lower values allow more of the Base colour or Skin Tone to show through, which can be useful for creating a more even appearance, like makeup foundation.
Tint
Adds a colour tint to the Albedo image. White = no tint.
Hue, Saturation and Value
The HSV of the Albedo image.
Base
This is like an undercoat for the Albedo image. The selected colour fills in the transparent areas defined by the alpha channel (if present). If you're using an Albedo image without an alpha channel, setting the Albedo Mix to 1.0 will completely obscure the Base color.
Base Mix
The Base opacity. Lower values allow more of the Skin Tone to show through, and higher values override the Skin Tone. Use this for skin tones that fall outside the normal human range.
Skin Tone Value
Like the Base property, this acts as an undercoat for the Albedo image, but is restricted to human skin tonal values. 0 = darkest, 1 = lightest.
Skin Tone Hue
Shifts the skin hue towards a warmer or cooler hue. 0 = coolest, 1 = warmest.
Subdermis
The colour beneath the skin surface. This is the Subsurface Radius setting, but replaced with a colour picker (you can still enter the Radius values by entering them in the colour picker's RGB fields). Note that the resulting colour will appear darker.
Subsurface
The Subsurface Scattering depth. The default setting remaps the Subsurface image (if present) to appropriate values.
Roughness
Uniformly lightens or darkens the Roughness image map, to make the skin appear more glossy or matte. This value, as well as the Roughness map itself, also affects the intensity of the procedural micro displacement
Displacement
Adjusts the intensity of the Displacement image.
Albedo, Subsurface, Roughness, Displacement Inputs
Inputs for the respective image maps and Albedo alpha channel.
UV Map
Connect the UV Map node to this input, and select the desired UV map in that node.
Skin Node Outputs
Shader
Connects to the Makeup node's Shader input.
Displacement
Connects to the Material Output node's Displacement input.
Customising the Skin Node Group
Refer to the Skin Shader Reference.pdf included in the Human Skin Shader folder for annotations on the inner workings of the Skin node group.
Makeup Node Inputs & Properties
Shader, Base Color, Subsurface, Subsurface Radius
Input sockets for the Skin node.
Eyebrows, Eyelids, Eyeliner, Cheeks & Lips
The following properties can be edited for each of the five makeup shapes, and their colours can be selected via the colour picker to the right of each.
Mix
The opacity of the makeup.
Color Mix
The colour opacity. If you want to change the other properties while keeping the original skin tone (e.g.. to just add gloss or metalness), set this to 0.
Metallic
Sets the metalness of the makeup.
Roughness
Sets the reflectivity of the makeup. Tip: for lip gloss, try adding some blur to the lips on the Displacement map, and paint the lips on the Roughness map completely black to eliminate the micro displacement.
Clearcoat
Adds an additional reflective layer to the lips.
Subsurface
The subsurface scattering depth. This option is only available for the lips due to an issue with the Mix Shader, and should be set to either 1.0 (SSS on) or 0 (SSS off) , as the in-between values do not produce expected or useful results.
Mask Inputs
Inputs for connecting the masks that define the shapes of the makeup.
Makeup Node Output
Shader
Connects to the Material Output node's Surface input socket.
Applying New Makeup
The Skin Shader includes five makeup masks. To replace them with your own makeup designs, follow these steps:
Select one of the mask image nodes.
Enter Texture Paint mode (the mask image should appear on the object).
Paint white to add to the makeup, or black to subtract from it.
Save the image when done.
Need More Makeup?
You can add more makeup masks by duplicating the Makeup node and its images, replacing the duplicated images with new ones, and connecting the nodes as shown below (Makeup node output > new Makeup node Shader input, Skin node outputs > Makeup node inputs, UV Map output > Image node inputs). In this way you can also create layered colour gradients.
