Ruby are a 3dPrinters best friend... ;)
First print the ring and optionally paint it. Then print the box, cut the foam to size and spray glue the velvet around it. Cut a slot in it with a knife, put it in the box and then put the ring in the slot, done :-)
I printed the box on the UM2+ and the ring on the Form1+, so i included custom support base and pin for the Formlabs printer, you might want to remove those if printing in another printer.