Constant

| Transparency/Reflection | Indirect Illumination | Render Tree Usage | Cook-Torrance

Category: Illumination

Shader Family: Surface Material

Output: Color

Sets the material of a constant color which is unaffected by illumination. This shader also allows you to apply a transparency on the constant color, as well as reflections and incandescence.

It is important to note that by default, mental ray clips color samples after each ray, before filtering them into the final pixel value. The Clip alpha below RGB mode first clips RGB values to the 0 to 1 range, and then clips alpha values to the MaxRGB to 1 range. If you need to preserve RGB color and intensity as well as accurate transparencies, you can set the Color Channel Clipping option to No Clip in the Framebuffer > Motion Data settings of the mental ray Render Options Property Editor [Properties Reference].

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

Illumination

Color

Defines the RGB components used in the output value. Default is light gray.

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 = grainy; high = smooth surface
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 glass is roughly 1.33.) 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 = grainy; high = smooth surface
Reflection Mode	Raytracing Enable lets rays 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

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

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. Also, you can a texture to control color input to create a constant texture.

Except where otherwise noted, this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License