Sketch

Below is my initial sketch. While sketching, I thought a lot about how the adapter would lay (straight, standing up, curved), how the lid would work (sliding, inlay, hinged), and how to incorporate a clip. It was tough because I had to "think" like the 3D printer, since it obviously wouldn't do hinges of any sort easily and definitely not a clip that had to flex. It was tough because I wasn't really sure how the materials would react or withstand certain pressures.

In the end, I decided to go with a sliding lid to keep it simple but loved the way the adapter laid in the case while curved. I decided to go with a store bought metallic clip that I can easily screw on after it was printed. In hindsight, I should've tried to 3D print the clip because the PVA had much more flex and strength than I originally thought.