The Hair shading model is specifically designed to render realistic hair and fur. It simulates the way light interacts with individual strands, including multiple specular highlights and anisotropic reflections. For enhanced realism, it can be combined with the Albedo Gradient shader to create color variations along the length of hair strands.
Use cases include:
- Rendering realistic hair, fur, or fibers.
- Creating varied hair colors and highlights using Albedo Gradient.
- Achieving fine control over strand orientation and light reflection behavior.
This shading model can use two texture maps:
- Radial Roughness Map (Grayscale): Controls the roughness of individual hair strands along their length. Lighter areas scatter light more, creating softer highlights, while darker areas produce sharper reflections. This allows for more natural and detailed hair appearance.
- Direction Map (RGB): Guides the direction of anisotropic reflections, defining hair orientation and creating diverse styles with realistic lighting.
Both maps can be painted in Toolbag using Texture Projects or authored externally in third-party applications.
| Setting | Description |
|---|---|
| Radial Roughness Map Texture Slot | Add a radial roughness texture by clicking on the slot or dragging and dropping one from the Library. |
| Channel Selection | Determines which channel of the texture map will be used. It’s useful when, instead of using multiple single textures, you use one texture with different grayscale maps in the different texture channels: Red, Green, Blue, and Alpha. |
| Radial Roughness Value | Specify how much the glints are smoothed in the direction of the hair normal. Too low values will concentrate the glint; while setting it too high will spread the light across the width of the strand. |
| Invert | Inverts the radial roughness values, providing the opposite appearance. |
| Direction Map Texture Slot | Add a direction texture by clicking on the slot or dragging and dropping one from the Library. |
| Scale & Bias | Remaps vector data from the range [0,1] to [-1,1]. Disable this setting with floating-point textures. |
| Swap X/Y Direction | Swaps the direction map content in the red and green channels. |
| Anisotropy Direction | Sets the direction in which the anisotropic reflections face. This value can be used for hair when all UVs point in the same general direction. |
