this is a parametric box with snap on lid. it is scaleable and has 4 mounts that you can position in z height and x,y location for a circuit board to bolt in on. it has rounded corners, ability to print just the cover or the box, and the ability to remove material easily as follows;
there is a section of code at the begining of the open scad file called remove(); any shape and location in this area will be subtracted from the box, so it is easy to make switch holes and led holes as well as vent holes. there is an example in that section that has been remarked out.
all you need to do is decide how big the outside of box should be, how big the inside should be and the screw mount positions as well as height. there are 4 positions by default. if you need more just use the module mount(); to add them.
this may not be the first electronics enclosure design, but it is what i needed to make a variety of different enclosures. thought everyone else would benefit from it as well.
for example it took less than 6 minutes to create an arduino box with this parametric box