I installed a slightly remixed version of the TeachingTech all-in-one electronics case (https://www.thingiverse.com/thing:3688967) when I added a Raspberry Pi for Octoprint in the back of my printer and now had a gap where the original electronics case used to be. I already had the case that I used as a source, so I thought I could just mirror the case in my slicer and use it on the other side. A great idea, but it did not fit. The mirrored case interfered with the existing case by about a millimeter. I remixed the case in Fusion 360 and slimmed it down so that the case and its mirror image both fit the printer.

With the electronics in the back, I no longer routed the display cables along the cross-bar of the printer, but now had them underneath the printer. This means that I no longer have to leave any room in the back for the cables, so I lengthened the case and the drawers to better fill the space. I did not modify the width of the drawers, only their length. Drawers designed for the original case should fit, but will not fill the length.

The case is set up for the right side of the printer. To print the left side you need to mirror the case and drawers.

Note that this design is for the Ender 3 only. It will not fit the Ender 3 Pro since that printer has a wider center extrusion (40 mm instead of 20 mm).

The case and drawers should print as they are with no supports.