This twist-and-lock glasses case is very easy to print and use. The two halves can be easily removed to put glasses into and then locked with a simple twist. The inner size is around 55 mm and should fit most glasses well. To connect the two sides, look at the flat side and position the non-hook side slightly above the hook side. The bottom of the non-hook's flat side should line up with the top of the hook's flat side. Check out the pictures above for where to position it. Then just twist them together and the flat side should line up. There are multiple print profiles containing both halves either together or separately so different colors (or the same color) can be used. Feel free to remix this design if you want to modify it. Printed on a P1P, but should work on other printers.

*Update: quick change to tighten the tolerances in the twist and lock mechanism for a better friction fit.