Overall Color – Specifies the overall coloration for the material. This color serves as a filter for both the diffuse and the sub-surface components. The effect is a color tint, where pure white means neutral and doesn’t introduce tinting. Diffuse Color – Specifies the color of the diffuse portion of the material. The Diffuse Amount needs to be greater than 0 for this option to have any effect. Diffuse Amount – Controls the strength of the diffuse component of the material by blending between the diffuse and the sub-surface layers. When set to 0, the material does not use the diffuse component. When set to 1.0, the material shows no sub-surface scattering. Values in between can be used to “harden” the surface while retaining the SSS effect inside when using larger Scatter Radius (cm) values. A texture in the Diffuse Amount can be used as a mask for the SSS layers to simulate dust or paint on the surface. Color Mode – Allows the user to determine which method is used to control the sub-surface scattering effect. Sub-surface Color and Scatter Radius – This mode uses a general Sub-surface Color and an inside Scatter Color that becomes visible in backlit parts of the objects that are thinner than the scaled Scatter Radius (cm). It is suitable for relatively opaque materials. Scatter Coefficient and Fog Color – This mode uses the Scatter Coefficient to define the outside scatter layer color and translucency, and the Fog Color for the respective inside values. The translucency for both components is multiplied by the scaled Scatter Radius (cm). This mode allows for control of the SSS components, similar to that in the V-Ray Material node. It is designed for translucent or refractive materials like juice or ice. Sub-surface Color – Specifies the general color for the sub-surface layer of the material. Note that the Sub-surface Color value is filtered/multiplied by the Overall Color and both filter the Scatter Color. Scatter Color – Specifies the internal scattering color for the material. Brighter colors cause the material to scatter more light and to appear more translucent; darker colors cause the material to look more diffuse-like. Scatter Coefficient – Specifies the outside color for the sub-surface layer of the material and also affects its outer translucency. Brighter colors cause the material to look frosted and less transparent, while darker colors result in a clearer effect. Note that the Scatter coefficient color value is filtered/multiplied by the Overall color. Available when the Color Mode is Scatter coefficient and fog color. Fog Color – Specifies the inside or backlit color of the object and affects its inner translucency. Brighter colors cause the material to scatter more light and appear more translucent; darker colors result in more diffuse-like look. The Fog color is filtered/multiplied by both the Scatter coefficient and the Overall color to achieve the final result.. Available when the Color Mode is Scatter coefficient and fog color. Scatter Radius (cm) – Controls the depth of scattering light inside the material for both color modes. Smaller values cause the material to have a shallower layer of scattered light and to appear more diffuse-like. Higher values define a deeper layer, where the material scatters light and make it looks more translucent. Note that the Scatter Radius (cm) value is always specified in centimeters. Phase Function – Specifies a value between -1.0 and 1.0 that determines the general way light scatters inside the material. Its effect can be somewhat likened to the difference between diffuse and glossy reflections from a surface. However, the phase function controls the reflection and transmittance of a volume. A value of 0.0 means that light scatters uniformly in all directions (isotropic scattering). Positive values mean that light scatters predominantly forward. Negative values mean that light scatters mostly backward. This, depending on the direction of illumination, leads to changes in the blending between the two SSS colors: boosts one or the other. Most water-based materials (e.g. skin, milk) exhibit strong forward scattering, while hard materials like marble exhibit backward scattering. Scale – Controls the depth of scattering by multiplying the Scatter Radius (cm). This can be useful when your scene was not modeled to scale. The default value of 1 means that the Scatter Radius (cm) is used as it is. For example, to render a 1:10 scale model, set the scale to 0.10. Index of Refraction – Specifies the Index of Refraction for the material. Most water-based materials like skin have an index of refraction of about 1.3. |