Generative Design for Aerospace Components
Typical request: "Make this bracket lighter while keeping it strong enough for load X."
- Define load cases, boundary conditions, keep-out zones, and manufacturing constraints (material, min wall thickness, printer build volume if additive).
- Run topological optimization (nTopology / Fusion 360 Generative Design / Grasshopper + Karamba) targeting mass minimization with stress/displacement constraints.
- Reconstruct a manufacturable mesh/surface (smooth organic shell, not raw voxel soup) unless printing directly from mesh.
- Validate with FEA re-check at full load + safety factor.
- Output: STEP/parametric model for CNC paths, or STL/3MF with lattice infill for AM.
No preamble — jump straight to constraints gathering when a task arrives.
Progress:
- [ ] Capture requirements: loads, materials, envelope, manufacturing method, interfaces (bolt patterns, mounting points)
- [ ] Choose approach: topology optimization vs. parametric (Grasshopper) vs. sculptural (ZBrush/Blender) vs. reverse-engineered (photogrammetry)
- [ ] Build/run model
- [ ] Validate (FEA, printability checks, interference checks)
- [ ] Prepare deliverables (CAD, mesh, drawings, VR review build)
- [ ] Document parametric drivers / scripts for reuse
Step details:
- Requirements capture: Always pin down non-negotiables first — mounting interfaces and envelope rarely change; everything else (internal structure) is optimization space. Ask for load cases in force/moment form, not vague "strong enough."
- Topology optimization: Set preserve/obstacle geometry for fastener bosses and mating faces before running the solver. Use symmetry constraints if the part is symmetric — halves solve time.
- Parametric (Grasshopper): Expose only meaningful parameters (envelope dimensions, hole patterns, wall thickness) via sliders/Human UI. Keep the definition modular: separate "inputs," "geometry logic," "outputs" clusters so it's debuggable and reusable as a library component.
- Lattice/voxel for AM: Match lattice type to loading (gyroid for distributed/fatigue loads, strut-based for directional loads). Always add solid skin shells (1-2mm) around lattice regions for surface quality and to avoid powder/support trap issues.
- Organic sculpting (ZBrush/Blender): Build surfaces at low-poly first for proportion review, then subdivide. Re-topologize or convert to NURBS (via ICEM Surf/Rhino/Power SubD-NURBS) before handing to CAD/CFD, since sculpting meshes aren't manufacturing-ready.
- Photogrammetry reverse-engineering: Shoot 60-80% photo overlap, diffuse lighting, matte spray on reflective parts. Reconstruct in RealityCapture/Metashape, then re-surface in CAD — don't hand raw scan mesh to manufacturing; extract reference curves and rebuild parametric features.
- VR review: Export at correct real-world scale, include at least the surrounding assembly/access panels, not just the isolated part — ergonomics review needs context (reach envelopes, tool clearance).
- Family generation scripts: Drive from a single master spreadsheet or Grasshopper data tree of scale factors; never hand-edit individual size variants — regenerate all from the parametric source whenever the baseline changes.
Example 1: Input: "Need a UAV landing gear bracket, titanium, printed, must survive 5kN vertical load, current design is 340g." Output: Load case + fixed interface points defined → nTopology topology optimization run with preserve geometry at bolt bosses and ground-contact face → bionic result reconstructed as smooth organic shell → FEA validated at 5kN × 1.5 safety factor, max stress < titanium yield/1.5 → final mass ~190g (44% reduction) → delivered as STEP (machined bosses) + STL with gyroid lattice fill in low-stress regions, 1.5mm skin.
Example 2: Input: "Build a parametric hatch family for different fuselage diameters in Grasshopper." Output: Grasshopper definition with inputs (fuselage radius, hatch width/height, hinge offset, latch count) → geometry cluster generating curved hatch panel conforming to fuselage curvature + frame cutout → outputs: surface for CFD, solid for structural, DXF flat pattern for composite layup → packaged as a reusable GH user object with Human UI sliders for non-GH users on the team.
Example 3: Input: "We have a competitor's pylon, no drawings, need to study it." Output: Photogrammetry capture (80+ photos, turntable + handheld for undercuts) → point cloud → mesh in Metashape → imported to CAD, reference planes/curves extracted from scan → parametric solid rebuilt matching key dimensions within ±0.5mm → flagged uncertain regions (occluded surfaces) for physical measurement follow-up.
- Always optimize with real load cases and factors of safety agreed with structures/stress engineers — don't let the algorithm's output substitute for sign-off analysis.
- Keep a clean separation between "optimization/exploration geometry" (meshes, voxels) and "production geometry" (parametric solids) — convert explicitly, don't ship raw optimizer output to manufacturing.
- Version and document every parametric script (inputs, assumptions, units) — these become institutional assets, not one-off files.
- For AM parts, design for the specific printer/process from the start (orientation, support strategy, min feature size) — don't optimize shape first and worry about printability later.
- Build parametric libraries bottom-up from genuinely standardized features (hatches, pylons, landing gear mounts) — premature over-parameterization of one-off parts wastes effort.
- In VR reviews, involve actual maintenance/ops personnel, not just designers — the point is catching ergonomics issues designers won't notice on a screen.
- Shipping raw topology-optimization mesh directly to production without re-surfacing — causes manufacturing/inspection headaches and poor stress concentration behavior at rough facets.
- Running generative optimization without locking mounting/interface geometry first, producing beautiful parts that don't bolt to anything.
- Over-parameterizing Grasshopper definitions with every possible variable exposed — makes them fragile and slow; expose only what actually needs to vary.
- Using lattice infill without solid skin — leads to trapped powder (SLS/DMLS) and poor surface finish/fatigue life.
- Treating photogrammetry scans as dimensionally authoritative without validating against physical measurement — scan accuracy degrades on reflective/featureless surfaces.
- Scaling a design "family" by uniformly scaling geometry instead of re-deriving from parametric logic — breaks wall thickness, fastener sizes, and manufacturing constraints that shouldn't scale linearly.