AL Surface Mtl

The V-Ray AL Surface shader is V-Ray's implementation of Anders Langland's alShader. It is designed to reproduce the appearance of skin. The current version takes into account diffuse reflection, two levels of reflection, and subsurface scattering.

Bump Amount – A multiplier for the bump map effect. A node socket is available for this property.

Bump Type – Determines how the Bump Map is interpreted. A node socket is available for this property.

Bump Map – Uses a bump map to determine the bump effect of the material.
Normal Map in Tangent Space – Uses a tangent normal map to determine the bump effect on the material.
Normal Map in Object Space – Uses an object space normal map to determine the bump effect on the material.
Normal Map in Screen Space – Uses a screen space normal map to determine the bump effect on the material.
Normal Map in World Space – Uses a world space normal map to determine the bump effect on the material.
From texture bump output – Uses the texture bump output to determine the bump effect on the material.
Explicit – Sets the normals to adhere to a specific value rather than being dependent on a face. As a result, any changes made to the position of a face do not affect the normals, which remain unchanged. 

Opacity – Assigns transparent properties to the material, where white is completely opaque and black is completely transparent. Textures can also be assigned to create a material that has a non-uniform opacity.

Diffuse Color – The color of the material. Note: The actual diffuse color of the surface also depends on the reflection and refraction colors. You can use a texture map for the diffuse color.

Diffuse Strength – A multiplier for the diffuse color. A node socket is available for this property.

Diffuse Bump Map – Specifies a texture as the bump or normal map for the diffuse component. The bump effect here is added to the Bump parameters bump effect. If no map is set in the Bump parameters or the map there is disabled, the map in this layer still produces its bump effect.

Diffuse Bump Amount – A multiplier for the bump map effect.

Diffuse Bump Type – Determines how the Diffuse Bump Map is interpreted.

Bump map – Applies the map as a bump map.
Normal map in tangent space – Applies the map as a normal map in tangent space.
Normal map in object space – Applies the map as a normal map in object space.
Normal map in screen space – Applies the map as a normal map in screen/camera space.
Normal map in world space – Applies the map as a normal map in world space.
From texture bump output – The map is applied as determined by map type itself.
Explicit normal – Applies the map as an explicit normal.

The AL Surface Material has two reflection sets with identical parameters for precise control over two types of reflection. 

Reflect 1 Color – The reflection color. Note that the reflection color dims the diffuse surface color. A node socket is available for this property.

Reflect 1 Strength – A multiplier for the reflection color. A node socket is available for this property.

Reflect 1 Roughness – Used to simulate rough surfaces or surfaces covered with dust. A node socket is available for this property.

Reflect 1 IOR – The IOR to use when calculating Fresnel reflections. Normally this is locked to the Refraction IOR parameter, but you can unlock it for finer control. A node socket is available for this property.

Reflect 1 Distribution – Determines the type of BRDF (the shape of the highlight):

Beckmann – Uses a Beckmann distribution for the reflection.
GGX – Uses GGX distribution for the reflection. The GGX distribution has a longer "tail" compared to the Beckmann distribution.

Reflect 1 Bump Map – Allows the user to attach a texture for the bump or normal map for the reflection component. The bump effect here is added to the Bump parameters. If no map is set in the Bump parameters or the map there is disabled, the map in this layer still produces its bump effect.

Reflect 1 Bump Amount – A multiplier for the bump map effect.

Reflect 1 Bump Type – Determines how the Reflect Bump Map parameter is interpreted.

Bump map – Applies the map as a bump map.
Normal map in tangent space – Applies the map as a normal map in tangent space.
Normal map in object space – Applies the map as a normal map in object space.
Normal map in screen space – Applies the map as a normal map in screen/camera space.
Normal map in world space – Applies the map as a normal map in world space.
From texture bump output – The map is applied as determined by map type itself.
Explicit normal – Applies the map as an explicit normal.

The AL Surface Material has two reflection sets with identical parameters for precise control over two types of reflection. 

Reflect 2 Strength – A multiplier for the reflection color. A node socket is available for this property.

Reflect 2 Color – The reflection color. Note that the reflection color dims the diffuse surface color. A node socket is available for this property.

Reflect 2 Roughness – Used to simulate rough surfaces or surfaces covered with dust. A node socket is available for this property.

Reflect 2 IOR – The IOR to use when calculating Fresnel reflections. Normally this is locked to the Refraction IOR parameter, but you can unlock it for finer control. A node socket is available for this property.

Reflect 2 Distribution – Determines the type of BRDF (the shape of the highlight):

Beckmann – Uses a Beckmann distribution for the reflection.
GGX – Uses GGX distribution for the reflection. The GGX distribution has a longer "tail" compared to the Beckmann distribution.

Reflect 2 Bump Map – Allows the user to attach a texture for the bump or normal map for the reflection component. The bump effect here is added to the Bump parameters. If no map is set in the Bump parameters or the map there is disabled, the map in this layer still produces its bump effect.

Reflect 2 Bump Amount – A multiplier for the bump map effect.

Reflect 2 Bump Type – Determines how the Reflect Bump Map parameter is interpreted.

Bump map – Applies the map as a bump map.
Normal map in tangent space – Applies the map as a normal map in tangent space.
Normal map in object space – Applies the map as a normal map in object space.
Normal map in screen space – Applies the map as a normal map in screen/camera space.
Normal map in world space – Applies the map as a normal map in world space.
From texture bump output – The map is applied as determined by map type itself.
Explicit normal – Applies the map as an explicit normal.

The SSS tab has three identical options for subsurface scattering control.

SSS Mix – Enables or disables the SSS options. A node socket is available for this property.

SSS Mode – Sets the Sub Surface Scattering Mode.

Diffusion – The diffusion method spreads light more uniformly inside the material. Note that it is not supported on V-Ray GPU.
Directional – The directional method tends to propagate more light in the direction from which the surface is lit.

SSS Weight – The relative contribution of the shallow scattering layer to the material. A node socket is available for all three instances of this property.

SSS Color – The color for the shallow scattering layer. A node socket is available for all three instances of this property.

SSS Radius – The distance that light is scattered within the shallow layer. A node socket is available for all three instances of this property.