We reproduced the ring using Fusion360, making the clip ramps and stress reliefs as close to the original as possible. The ring is then 3D printed using Acrylonitrile-Styrene-Acrylate (ASA - a successor polymer to ABS, the material used for the OEM ring. ASA has similar properties with the added benefit of being UV stable.)
As a 3D print, these rings are subject to minor imperfections and ridges in the surface. If a smoother finish is desired, the material can be treated with Acetone.