HumanSkin Shader
Overview
The HumanSkin shader is a specialized shader for rendering skin surfaces as skin shading cannot be accurately reproduced using regular lighting models.
HumanSkin Shader Params
| Shader Params |
Description |
Shader gen option |
| Displacement bias |
See Tessellation and Displacement for more information. |
Displacement Mapping |
| Displacement height scale |
See Tessellation and Displacement for more information. |
Displacement Mapping |
| Fresnel Bias |
See Illum Shader for more information. |
All |
| Fresnel power |
See Illum Shader for more information. |
All |
| Fresnel Scale |
See Illum Shader for more information. |
All |
| Indirect bounce color |
See Illum Shader for more information. |
All |
| Inner layer anim frequency |
Sets how fast the inner layer animates. (is relative to the depth) |
Multilayer |
| Inner layer anim phase |
Set animation phase. |
Multilayer |
| Inner layer depth |
Sets how deep or close to the surface the inner layer is. |
Multilayer |
| Inner layer diffuse |
Sets the diffuse color of the inner layer. |
Multilayer |
| Melanin |
Sets level of melanin. |
Default |
| Oil spec glossiness |
Glossiness of secondary "oily" specular highlight. |
Default |
| Oil spec multiplier |
Multiplies the intensity of the secondary "oily" specular highlight. |
Default |
| Outer layer opacity |
Sets how opaque the main diffuse (surface) is shown over the inner layer. |
Multilayer |
| Rim multiplier |
Multiplies the intensity of rim light on the surface. |
Default |
| Scattering radius |
Radius in which light travels through the surface of skin before exiting. |
Default |
| Tessellation face cull |
See Tessellation and Displacement for more information. |
Displacement Mapping |
| Tessellation factor |
See Tessellation and Displacement for more information. |
Displacement Mapping |
| Tessellation factor max |
See Tessellation and Displacement for more information. |
Displacement Mapping |
| Tessellation factor min |
See Tessellation and Displacement for more information. |
Displacement Mapping |
Basic information and limitations
- The new shader uses screen-space SSS by default. The old wrap method has been deprecated (doesn't work with deferred lighting).
- Multilayer option has been modified to accommodate this change.
- Self shadowing has been removed due to artist feedback.
- Due to current hardware limitations, the subsurface scattering has a limited number of samples and thus will create artifacts with high scattering values.
- There is unfortunately no way around this issue aside from tweaking light conditions to hide the artifacts, or avoid using high scattering values.
- The best practice is to hover around the default value and ensure that your character never gets too close to the screen.
- There is no translucency in thin areas such as the nose or ears because of deferred lighting limitations.
Using the HumanSkin shader
Subsurface Scattering
Skin's main look is the result of subsurface scattering (light bouncing inside the surface, exiting in a different location than where it entered). Without subsurface scattering skin appears hard like concrete. It's the most important visual cue for the look of skin, therefore great care has been taken into faithfully simulating the effect. See Subsurface Scattering for more detail.
- Scattering radius: defines the radius of scattering light inside the surface. The lower the value, the less scattering occurs and the more "concrete" the surface looks. Higher values provide a larger sense of translucency but too high can make the surface look like Wax or cause artifacts (this is because of a limited number of samples due to hardware constraints).
 |
 |
 |
| No scattering, looks like concrete (radius 0) |
(Default) Mild scattering, very fleshy (radius 2) |
High scattering, kills look (radius 8) |
Rim Lighting
Rim Lighting simulates light reflection at sharp angles, meaning that it enhances visualization of silhouette shapes, separating surface (making it more visible) from the background. See Rim Lighting for more detail.
- Rim Multiplier: Sets rim lighting intensity/multiplier. Note that rim lighting on brighter skins tones should be very subtle and more visible on darker tones.
 |
 |
 |
| No rim, flat |
Subtle rim, interesting look |
Strong rim, kills look |
Oil specular
Oil specular simulates the specularity caused by a thin layer of oil over the skin.
- Oil spec glossiness: Glossiness/sharpness of the oil specular highlight. Higher values give a more wet look but too high can break the effect.
 |
 |
 |
| No oil gloss, looks ok |
Mild oil gloss, gives more interesting look (particularly in ambient lighting) |
Strong oil gloss, too sharp, kills look |
- Oil spec multiplier: Controls the intensity of the oil specular highlight.
| |
|
 |
| No oil spec, a bit dull |
Mild oil spec, gives nice look |
Strong oil spec, too strong, kills look |
Glossiness
Glossiness is controllable via a gloss map stored in the specular map alpha channel. It is highly recommended that all major characters have a gloss map (at least for their face) as it gives variation to the specularity of the skin.
 |
 |
 |
| No glossiness, too diffuse |
Gloss map with glossiness 200 (for females, lips could be nice and glossy) |
No gloss map with glossiness 200, way too strong, kills look |
Decal overlay
Textures placed in the Decal texture slot will be overlayed over the diffuse texture. For example, this can be used for war camouflage for soldiers, dirt, fake shadows or ambient occlusion.
 |
| Dirt added using decal texture |
