2008

Luninance takes surface properties into account.
For best results, render with mental ray or another renderer that supports
32–bit floating-point output and set the output format to PIC, HDR, or
EXR. If using the scanline renderer or another renderer that doesn't support
32–bit floating-point output, set the Scale Factor parameter, which acts as
a multiplier, to adjust the range of values for the output data.
■ Material ID: Retains the material ID information assigned to an object.
This information is useful when you are making selections in other
image-processing or special-effects applications, such as Autodesk
Combustion. For example, you could select all of the objects with a given
material ID in Combustion. The material ID corresponds to the value you
set for the material with the material ID channel. Any given material ID
will always be represented by the same color. The correlation between a
specific material ID and a specific color is the same in Combustion. See
Material ID Channel on page 5252 .
■ Matte: Renders a matte mask, based on selected objects, material ID channel
(effects IDs), or G-Buffer IDs.
The Matte element displays an additional Matte Texture Element rollout
on page 6164 .
■ Object ID: Retains the object ID information assigned to the object.
Roughly comparable to the material ID, the object ID information is useful
for selecting objects based on an arbitrary index value in another
image-processing or special-effects application. If you know that you will
6146 | Chapter 18 Rendering