Cook-Torrance

| Transparency/Reflection | Indirect Illumination | Render Tree Usage | Render Tree Usage

Category: Illumination

Shader Family: Surface Material

Output: Color

Controls the ambient, diffuse, and specular RGB colors, as well as RGB reflectivity, translucency, and transparency. Also controls color shifts with angles.

Name	The shader's name. Enter any name you like, or leave the default.

Illumination

Enable	Switches on or off the Diffuse illumination component of the shading model.
Diffuse	Defines the surface color in the illuminated area of the object. This value is blended with the object's Ambient value.
Ambient	Determines the color of the global ambiance (indirect illumination) that affects the object.
Specular	Defines the color of the object's surface highlight.
Refraction	Defines the index of refraction for the specular, which varies according to the nature of the material.
Roughness	Controls the width of the specular highlight.

Transparency/Reflection

Transparency

Enable

Switches on transparency. When off, no transparency is possible on an object.

Mix Color

The Mix color controls are a subset of the Transparency controls. They include the Color, Use Alpha, Invert, and Scale controls.

Color	Defines the material's color transparency. Black = opaque; white = transparent
Use Alpha	Uses the material's alpha channel, instead of its RGB, channel to control transparency. This is especially useful when you are driving the transparency with an image that has a matte.
Invert	Inverts the color or alpha value that is driving the transparency, depending on whether or not Use Alpha is enabled.
Scale	Adjust this value to adjust the intensity of the transparency. If the Invert option is enabled, the scaling is applied to the inverted value.
Frost	Determines the smoothness of the surface. 0 = glossy; the higher the value the more diffuse, or "frosted," the effect
Samples	Specifies the number of times the light ray is sampled. Low sample rate for a grainy; high for smooth
IOR (Index of Refraction)	Controls the bending of light through a transparent material. Defines the index of refraction, which varies according to the nature of the material. (The refractive index of water is roughly 1.33, and that of vodka is about 1.36.) Default = 1 (the refractive index of air), which allows light rays to pass through a transparent material without distortion.

Reflection

Enable

Switches on reflection. When off, no reflection is possible on an object.

Mix Color

The Mix color controls are a subset of the Reflection controls. They include the Color, Use Alpha, Invert, and Scale controls.

Color	Determines the blending factor between the illumination of the front and back of the object. The default value of 0 results in no blending.
Use Alpha	Uses the material's alpha channel, instead of its RGB, channel to control reflection. This is especially useful when you are driving the reflection with an image that has a matte.
Invert	Inverts the color or alpha value that is driving the reflection, depending on whether or not Use Alpha is enabled.
Scale	Adjust this value to adjust the intensity of the reflection. If the Invert option is enabled, the scaling is applied to the inverted value.
Gloss	Determines the smoothness of the surface. 0 = glossy; the higher the value the more diffuse, or "frosted," the effect
Samples	Specifies the number of times the light ray is sampled. Low sample rate for a grainy; high for smooth
Reflection Mode	Raytracing Enable allows rays to reflect off the surface to produce realistic reflections. This option is slower to render than Environment Only, which performs a quick reflection of a scene's environment shader.

Indirect Illumination

Global Illumination / Caustics / Final Gathering

Radiance

Used to control the color and intensity (strength) of the GI/FG/Caustic effect over the object's surface. Also, you can texture this parameter in order to reveal a GI/FG/Caustic effect on a given location on the object.

Translucency

Enable	Switches on translucency. When off, the surface has no translucent qualities.
Translucency	Determines the blending factor between the illumination of the front and back of the object. Default value of 0 gives no blending.

Incandescence

Enable	Switches on incandescence.
Incandescence	The color of light that a material appears to be emitting. Note that incandescent objects do not actually illuminate other objects.
Intensity	Sets the pixel brightness of the incandescence.

Render Tree Usage

This surface shader can be used almost anywhere in a render tree. Although it is most commonly connected directly to a material node's Surface input (as well as Shadow and Photon), you can use any number or combination of surface shaders to control various parts of your effect. Surface shaders are often mixed (as the Base Color using a mixer shader) with textures to add realism to them. Also, you can use textures to control color inputs (such as Diffuse or Ambient) or scalar output nodes (such as gradients or fractals) to control refraction or translucency.

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