I started with a big box with foam insulation but ran into a few issues. First a box shape was excessive due to the Ender 3 not using the full space and the box didn't fit well into corners. This inspired the octagonal shape you see today. Additionally, I added a angled window and a light to better view prints without the need to open it.

My previous design got too hot due to the insulation and having the electronics inside the enclosure caused the motherboard to break. That is why the electronics are on the outside and the insulation was omitted. The enclosure still gets warm enough to easily print with ABS. (other materials have not been tested)

Additionally, I created a custom bearing for the filament to role on to avoid friction caused issues.