3D Printer Use Case: Repairing a Dented Lens Filter Ring

I dropped this ancient Schneider-Kreuznach Retina lens on the floor, dinging the filter ring:

To repair it, I 3D-printed two plastic pieces (in HIPS with 100% infill) one matching the inner diameter of the filter ring, and the other matching the outside diameter:

Some ugly use of a C-clamp (the clamp's thread managed to put some marks on the opposite side of the lens filter ring, d'oh!):

And the result: leaves something to be desired, but still an improvement over the original damaged filter ring.