This is a specialized material that adds a dielectric (Reflection + Transmission) component to the geometry. It duplicates the features of Dali Physical.
Reflection
A non-physical parameter that determines the color and intensity of the reflection. To comply with physics, the product of all reflection components must be strictly 1.0 for the entire spectrum. An additional factor, the Fresnel coefficient, will be used in any case.
Edge
This is a non-physical parameter that interpolates the reflection color between R and Edge depending on the Fresnel coefficient. Must be 0 to match physics.
Retro
Defines
- The share in the total reflection energy and
- Color with intensity
for Retro reflection.
Transmission
This is a physical parameter that determines the hue when a beam passes through a dielectric. If the Depth parameter is specified, then the Transmission value is the color that the white light will acquire after traveling the Depth distance.
Depth
Determines the distance at which white light will acquire the hue specified in the Transmission parameter.
Light in a material decays exponentially, and different wavelengths decay at different rates. This parameter sets the "speed" of the decay.
Thin
The option enables the mode when the material is considered thin (like a sheet). When the option is off, when it collides with the front side of the surface, the light penetrates into the interior of the material and gradually fades. In this case, the system of nested dielectrics is used. After hitting the back side of the surface, the beam exits the material.
IOR
Refractive index (real part). For a dielectric, it determines the strength of reflection and the amount of refraction. For metal, it determines only the strength of reflection. Can vary across the spectrum, in which case interesting spectral effects of color dispersion are possible.
Faked shadow rays
To achieve low noise results, all renderers use a special mathematical procedure to combine separate tracing techniques: from point on geometry to lights and from lights to point on geometry. For the second technique, in the case of refractive dielectrics, it is impossible to calculate the visibility of the light source, because the path of light is not straight. Those, the second technique in such conditions is not applicable. This leads to a very high noise level. This option disables dielectric physics and allows the use of a second technique, which results in noise reduction. The limitation is the absence of caustics for such material.
Nesting priority
The priority of the material that the nested dielectric system will use.
Roughness type
Selects the model that will be used to calculate the Roughness of the material, if any.
GGX and Beckmann models are available.
Base
The value of the roughness of the material. 0 - smooth surface, 1 - completely rough. At high roughness values, there is some energy loss and darkening of the result.
Roughness can be varied across the spectrum by setting different values for different wavelengths. This opens up wide possibilities for shading.
Anisotropy
Roughness difference along the U and V axes. Can be changed along the spectrum by setting different values for different wavelengths.
Rotation
Rotation of the U and V axes. Can be changed across the spectrum by setting different values for different wavelengths.
Spectral range
Specifies the interval of the spectrum on which the spectral splines are defined.
