LuxRender Textures Fresnel - LuxRender Wiki
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LuxRender Textures Fresnel

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The fresnel textures are special textures used for loading optical data. They are neither float nor color textures, they are their own type entirely and cannot be used on normal fields.

Contents

Fresnel Texture Types

Constant

  • Output value: fresnel

Description

The constant texture is the simplest fresnel texture, it takes a single value, an index of refraction. This texture is not well-suited to using glass2 with dispersion enabled! One of the other fresnel textures should be used instead.

Parameters

Cauchy

  • Output value: fresnel

Description

The cauchy texture takes values to Cauchy's Equation, either n and b, or A and b, you can choose which.

Parameters

  • Use IOR: Enter a value for n and b and let LuxRender solve for A, rather than entering A and b and solving for n. Values for n and b are often easier to find on the internet.
  • IOR: If Use IOR is enabled, you can enter the value for n here. It is the same as the IOR field for constant.
  • A: If Use IOR is disabled, you can enter the value for A here.
  • b: The value for b, this value is required.

Sellmeier

  • Output value: fresnel

Description

The Sellmeier texture allows you to enter optical properties using the Sellmeier Equation

Parameters

Sellmeier has six parameters normally, and an optional seventh for A. These are the values of the same name in the Sellmeier Equation. Note that wavelengths are in ┬Ám, not nm!

  • B1
  • B2
  • B3
  • C1
  • C2
  • C3
  • A: This value is not required, but you can add it if you have it.

Fresnel Color

  • Output value: fresnel

Description

The fresnel color texture generates an IOR dataset based on an input color. The resulting dataset is designed to make a specular surface reflect the input color. This texture is primarily used to apply arbitrary colors or textures to the metal2 material. You can also use it for the volumes of glass2, but it will only give the target color for the reflection. The transmitted light will be left with the non-reflected light, essentially being the complementary color of the reflection.

Parameters

  • Reflection color - The intended reflection color of the material


Fresnel Name

  • Output value: fresnel

Description

Frensel name is a measured nk data loader. It has several built-in presets, and also includes the option to specify an nk file in the sopra or luxpop formats.

Parameters

  • File - An external file containing an nk dataset. If no file is found, a preset will be used.
  • Name - the name of a preset that should be used. You only need to specify either the name or the file parameter, not both. (If you specify both, the file will be used as long as a valid file can be found)


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