Fully Parametric Box

I made corners more round as the wall thinkness is constant there too.
The lid is not optional. lid_height = 0 means no lid.

Edit: wall_thickness should be an even product of the nozzle width for optimun path. At least with Cura wall_thickness = 1.2 with 0.4 nozzle created a lot of travels and many of them without retraction. With wall_thickenss = 0.8 this does not happen.

Edit2: It seems some corner issues (to get perfect parallel paths) are sometimes there with either cura or slic3r. It