Renders 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 want to select several objects at once, at a later time, you can assign them all the same object ID in 3ds Max. By rendering with the object ID, this information will be available in other applications.
You assign the object ID with the Object Properties dialog 
General panel Object ID parameter. A given object ID is always represented by the same (arbitrary) color. The correlation between a specific material ID and a specific color is the same in Combustion.
When an Object ID entry is highlighted in the element rendering list, the Object ID Element rollout appears on the Render Elements panel. This rollout lets you choose whether to base the render color of a given object ID on the object color or the Object ID. If you choose Object Color, the render color is the object's base color, as shown on the Create panel Name And Color rollout and at the top of the other command panels, and is not based on the Object ID. If you choose Object ID, an arbitrary color is assigned to each object based on its Object ID.