I had this old case laying around that I was throwing some of my knives in - then I remembered I had a 3D printer.
These organizers are meant to fit inside a case that is 7.75" x 12" x 2" internally. The bottom trays are just partitions (no base to save on filament). The top trays nest into the bottom partitions and has enough room to allow me to zip the case shut. I designed this specifically for my knives and multi-tools since they seem to be laying around everywhere. The partitions and trays are mirrored in the slicer to get both sides (a total of 2 partitions, and 2 trays)
Here is a case that has the dimensions for this organizer (21cm x 31cm x 5.5cm): https://www.amazon.com/SUREWO-Waterproof-Carrying-Compatible-Session/dp/B07FDB8DBH?ref_=ast_sto_dp&th=1
The author marked this model as their own original creation.