My very first very simple 3D model for some sunglasses that were laying around in a drawer.

Fits 4 regular sized glasses/sunglasses.
Or other stuff that fits into 154x45mm compartments. 
The whole tray is 195mm x 160mm. 

No real challenge or tips for printing. 
Took me about 2,5h with a Flashforge Adv 5M.

Modelled in SketchUp. After loading the .stl in Orca Slicer, the tray has some funky looking walls but I didn't experience any issues with slicing or printing.