LURE-A | Care built into the geometry: hollow-body CAD case study

A small hollow body deserves the same care as a complex assembly: clear requirements, independent checks and a handover that explains each important decision. THE PROBLEM For this original 80 x 24 x 28 mm two-piece study, I wanted the geometry, calculated volume and exported files to tell the same checkable story. THE INVESTIGATION An independent ellipsoid-shell equation exposed a roughly 0.23% discrepancy in the default CAD volume calculation. Investigating the integration settings resolved the discrepancy: the reimported STEP volume agrees with the equation within 0.002545 mm3. I preserved the initial results, removed collapsed STL pole facets, tightened the mesh and checked both individual halves for paired edges, consistent winding, scale and volume. The assembled visualization is kept separate from the part files. THE PROCESS THINKING The 2.4 mm ideal minimum-wall bound is tied to an explicit extrusion-line and surface-error scenario. Eight STEP sections are checked against independent area equations. The candidate print setup considers seam orientation, bed contact, cavity-roof supports and bondline review. The setup checklist requires machine settings and toolpath review for the selected process. THE PHYSICAL THINKING A mass/displacement ledger includes cavity air, ballast and incoming water. Size and density sensitivity guide the inspection plan: coupon, dimensions, dry assembly mass, displacement, seam/water-uptake testing and a measurement-aware acceptance decision. The boards show why these checks matter to the result. DELIVERABLE APPROACH AI-assisted parametric Python CAD (build123d/OpenCascade), STEP, separate STL parts, review drawings and traceable check results. Each critical requirement is connected to its units, assumptions, acceptance limit and evidence. Original self-initiated, unbuilt study. Numerical results and process scenarios are identified in the images; actual printing and physical measurements remain the next validation stage. This body study does not include hook retention or verified swim action. Arya Singh | Independent Designer | Innovative Solutions Contractor