1. With Multiple Objects selected it will find objects that are cloned on top of each other resulting in animation flickering
2. With a Single object selected it will find and select faces that are coplanar
To select all faces which are coplanar use the list-box to "Select All", or
To select only those faces which are copies of the original, use "Select Only Duplicates"
1. Run script
2. In Max goto "Customize->Customize User Interface...->Toolbars tab->Category: ColinScripts" and drag "Find Coinstances" to a toolbar, click to run.
3d Model/Texture Artist