The RCP KIT for "Reusable Camo Patch". You can attach camouflage, whether natural or artificial, to your equipment. They were created to avoid using nets on the weaponry, and thus limit shooting incidents by blocking the ejection chamber and gas concentration. But also for the scopes in order to break the characteristic lines and the access to the adjustment rotary knobs without hindrance.
Adding 3D via the Reusable Camo Patch will provide the shadow needed to create the depth of your trompe l'oeil.