| Color Matte

Category: Processing > Color Channels

Shader Family: Texture

Multiple Outputs: Color and Scalar

The RGBA Split shader allows you to output the color (RGB) channels separately from the alpha channel.

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.

Render Tree Usage

Used to connect any image clip or material to the input and split out the color (RGB) channels from the alpha channel for use elsewhere in the render tree. The RGBA Split shader has the following output ports:

combined	Outputs the combined result. This passes all the data through exactly as input. Essentially, the result is not split. If the RGBA input is (0.2, 0.3, 0.4, 0.5) then the combined output is (0.2, 0.3, 0.4, 0.5).
rgb	Outputs the Red, Green, and Blue color components. If the RGBA input is (0.2, 0.3, 0.4, 0.5) then the rgb output is (0.2, 0.3, 0.4, 1.0).
alpha	Outputs only the alpha channel. If the RGBA input is (0.2, 0.3, 0.4, 0.5) then the alpha output is (0.5).

The render tree examples below show the results of the available outputs:

combined result

rgb result

alpha result