A simple board game insert I made for the paper box version of Codex Naturalis as practice after the first two hours of introducing myself to FreeCAD. The insert fits all game components, while the lid can be closed completely and the box can be stored vertically either without the pieces leaving their dedicated slots - one for the player tokens and two for the card decks. The player board is slotted in on top securing the former ones at their places.

I went with the settings the slicer application offered by default:

• layer height: 0.2 mm
• no support is needed

Improvement for a later variant could be distancing the card slots a bit to allow grabbing the bottom of the deck with your finger as it was originally intended. It is certainly a design flaw as it is but other than that works perfectly.