Microsoft KB Archive/167432

= Microsoft Knowledge Base =

HOWTO: Apply Effects to a Region Defined by the Alpha Channel
Last reviewed: April 25, 1997

Article ID: Q167432

The information in this article applies to:


 * Softimage Eddie for IRIX, versions 3.2a, 3.2b

SUMMARY
This article demonstrates how to apply an arbitrary effect, such as Color map or Mix, so that it only affects the region that is defined by the alpha channel.

MORE INFORMATION
To implement this procedure, do the following:


 * 1) Attach the image that has an alpha channel defining a specific region to the source target.
 * 2) Attach the same image to the OptionalBackground target of that tool.
 * 3) In the Input Editor, select the A-atop-B blend (the fifth one from the left in the top row).

As you modify the parameters, the changes only occur inside the region defined by the alpha channel.