I’ve been trying to learn OnShape, so for my first project I decided to design the box shape that I used for my rosary box here:
It was a fun challenge! The parameters are length, width, height, thickness (of material), and wing (which is the distance the curved portion sticks out on each side).
Here is a link to the OnShape file: https://cad.onshape.com/documents/3125dccc009d362332842d77/w/7a3b374d36ff312ce6fdc16c/e/d1ff4128ce3d6b27c0cd9d61
I didn’t model the top since there are so many choices for a top and you can do it yourself so easily.
Edit: forgot to say that this model assumes you are going to engrave the slot for the bottom at least halfway through the material. If you don’t you will have to adjust the box bottom dimensions.