A proper project enclosure in four printed parts: two rounded shells that screw together with flexing tabs, plus front and back panels that slide into internal rails — the design made famous by the Ultimate Box Maker, rebuilt on a CAD kernel and verified against the original to the cubic millimeter. Set the outer size first, then the features: side vents for airflow, PCB standoffs sized for #4 screws (give it your board's dimensions and hole inset), and the corner rounding that gives it the classic look. Panels are blank in this version — drill or cut openings to suit your build. Print tip: all four parts print flat without supports. The one-plate 3MF lays them out together; #4 (or M3) screws bite straight into the printed tab holes.