In BMC Remedy AR System, a copy of an object that is used in place of the origin object. Overlays are created in the Base Development mode of BMC Remedy Developer Studio. To ensure that customizations are preserved during upgrades, you modify the overlay, not the origin object. During upgrades, the overlay is ignored whether or not the upgrade program modifies the origin object definition. After the upgrade, AR System continues to use the overlay in place of the origin object. See also Best Practice Customization mode, origin object, overlaid object, and unmodified object.