The 3Delight Material is a general purpose, physically plausible, dual-layer material that can be used to render a large variety of surfaces, including the ability to simulate surfaces that have a coating. Coated materials include common real world objects such as furniture, cars, toys and many plastics. The coating layer adds interesting effects on gazing angles and adds an additional specular highlight (from the coating itself) that can be observed on most coated materials (it is especially noticeable on car paint and many legacy shaders simulate this effect by having a secondary highlight control, which is not physically plausible). Bump mapping can be applied to either/or the coating and the base layer. Additionally, it can be used in conjunction with displacement.
Coating | |
On | Specifies wether or not there is a coating on top of the Base layer. Visually, the presence of coating adds the following two phenomenas to the look of the layer:
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Color | The color of the coating. Light that travels through the coating will be coloured according to transmittance. The following images have been rendering with a white Colour so that it can be compared to the images in the Color section. |
Reflectivity | Specifies the degree of reflectivity through a normalised range. The more there is reflectivity on the coating, the less light goes to the base layer. In the following progression, a blue coating layer is more and more present with higher reflectivity. |
Roughness | This controls the specular roughness of the coating material. The smaller the value, the smoother is the surface of the coating. |
Thickness | Thickness of the coating in scene units (world units). For example, when rendering a coated table of 1 meter, a value of 0.001 means a thickness of 1 millimeter. In the image below, note how the thickness of the coating makes the highlights of the base surface less and less visible. With a very thick coating, as in the rightmost image, the rough highlight of the base layer is not visible anymore ans is replaced by the highlight of the shinier coating. |
Base Layer | |
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Diffuse | |
Color | Specifies the diffuse color of the base material. |
Roughness | This controls how diffuse is the material. A value closer to one simulate very rough materials such as chalk. A value of 0 renders a standard "lambertian" diffuse. On a more technical note, this parameter controls the roughness of the Oren-Nayer diffuse model. |
Reflection | |
Color | Specifies the color of the specular highlight. |
Reflectivity | Specifies the degree of reflectivity through a normalised range. This indirectly controls the index of refraction and fresnel that will be used for reflection. |
Roughness | This controls the specular roughness of the base layer. The smaller the value, the smoother is the surface. |
Anisotropy | Specifies anisotropy "directionality". 0 means no anisotropy. Positive values will increase anisotropy along the anisotropy direction and negative value will increase it along the perpendicular direction. |
Anisotropy Direction | Specifies the anisotropy direction in local tangents space. |
Incandescence | |
Color | Specifies the incandescence color. |
Intensity | Specifies the incandescence intensity. |
Subsurface | ||||
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On | Specifies wether or not the material has subsurface light penetration. | |||
Scattering | The tint of the light that is scattered inside the material. Visually, this means that the light which penetrates the object far away from its exist point will be tinted by this color. For skin, this would be bluish. | |||
Scattering Scale | Scattering isn't usually confined to the 0..1 range (physically, it is expressed in 1/mm). So to have a use friendly UI in which the scattering can still be expressed as a color, we added a separate scale to control the general amplitude. | |||
Transmittance | Visually, this specifies the color of the light that is diffused nearby the entry point of a light beam. For skin, this would be reddish. | |||
Transmittance Scale | Same as for Scattring Scale but applies for Transmittance. | |||
IOR | The index of refraction of the based layer. | |||
Scale | A global scale that applies to this material. Larger scales will make the object appear more translucent. This is the best way to control how much diffusion goes into the surface. A scale closer to 0 will tend to disable the subsurface scattering effect and the surface will look solid.
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