StiffMap: Volumetric Slice-Based Pre-FEA Bending Stiffness Profiler for Injection-Moulded Plastic Parts in CATIA V5

This technical report presents StiffMap, an original R&D tool developed in CATIA V5 VBA that automatically slices any 3D solid plastic part into volumetric cross-sections and extracts the true second moment of area (I) per slice — a quantity CATIA does not expose programmatically through its 2D inertia interface. The tool derives I_area = I_mass / (ρ·t) from first principles, converting the 3D mass inertia tensor (which CATIA does expose via GetInertiaMatrix) into the 2D area moment of inertia — unlocking bending stiffness EI(x) as a fully automated output along both transverse axes. Applied to a sample plastic part, the tool identified a 43% bending stiffness discontinuity at the fin-to-plain-wall transition — the highest-probability failure zone — in under 5 minutes, without FEA. Pre-FEA geometry review time reduced from several hours to under 5 minutes.