I need a 3D-printable bracket that snaps securely into a standard ISO corner casting on a shipping container without any drilling or welding. Once locked in place, the bracket must offer slotted mounting points that line up with the common wall mount supplied with VOOJOY-style solar floodlights. Key requirements • Load capacity: design for a medium weight fixture in the 5–20 kg range. • Material: I am leaning toward PETG or PLA, so the geometry must respect their strength limits and typical printable tolerances. • Fit: the piece must latch firmly into the corner casting opening and resist wind vibration. I don’t have fixed dimensions yet, so I will rely on your guidance to balance print size, part strength, and ease of insertion/removal. • Universal slots: the face plate should include elongated slots or hole patterns that accept most VOOJOY solar light brackets out of the box—ideally with a little side-to-side play for alignment. Deliverables 1. Parametric CAD model (STEP or Fusion 360) 2. Print-ready STL file(s) 3. Assembly or usage note showing how the part indexes into the ISO casting and where the light bracket bolts on Acceptance will be based on clear insertion into the corner casting in a simple mock-up, correct slot spacing, and basic FEA or hand-calc evidence that the design handles the specified load with PETG or PLA.