Location: The Render Manager > Renderer > Framebuffer
or
The Render Manager > Globals > mental ray > Framebuffer
The Color Control on the Framebuffer tab of the mental ray Rendering Options property editor allow you to activate various basic image processing options that are then performed during rendering. The following processes are available:
• Premultiply with Alpha automatically multiplies an object’s RGB values with their associated alpha value. This precomputation is helpful if you want to composite the object image later on.
• Dither 8-bit Frame Buffer simulates colors in the image to create a smooth gradation between areas of light and dark resulting in a very low slope of color variation.
• Desaturation Colors when Clipping activates the desaturation color–clipping method that looks at each RGB color component to identify any pixels that may have a value greater than 1. If such values exist, the values of all other pixels are reduced proportionally.
• Color Clipping defines how colors are clipped to a 0 to 1 range if they are not being written at floating-point precision. In all modes, the RGB components are clipped as specified by the desaturate option. Both the RGB and Alpha modes ensure that the resulting color is a valid premultiplied color.
The following modes are available:
- 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. Use this mode when you need to preserve RGB color and intensity, but the alpha channel is less important.
- Clip RGB above alpha mode, alpha is first clipped to the 0 to 1 range, and the RGB is clipped to the 0 to A range. This mode is useful for alpha compositing, since its is more important that the transparencies are correct and less important that RGB color and intensity are correct.
- No Clip turns off color channel clipping.
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