industrial-product-design

Industrial Product Design

Make the product credible before making the drawing polished. Integrate user tasks, architecture, form, interfaces, motion, CMF, manufacturing, service, and safety into one revision-bound design.

Portability Contract

• Keep the workflow independent of Codex, Claude Code, a CAD vendor, and a specific MCP namespace.
• Discover actual tools and capabilities before selecting a modeling route. Never invent a tool call or validation result.
• Keep editable native CAD as the design authority. Treat STEP, GLB, STL, renders, PDF, and DXF as derived evidence.
• Preserve source files and unrelated geometry. Use document IDs, revisions, configurations, and absolute paths to bind every mutation and output.
• Mark missing inputs TBD, skipped checks NOT_EVALUATED, and assumptions explicitly. Do not turn missing evidence into a pass.

Skill Boundary

• Use this skill upstream for product intent, concept selection, architecture, proportion, interaction, form language, interfaces, configurations, motion, CMF, and design maturity.
• Use mechanical-drafting-gbt downstream for GB/T views, dimensions, fits, GPS/GD&T, BOMs, manufacturing notes, DRC/DFM, plotting, exchange verification, and release packaging.
• Do not duplicate drafting rules here. Do not start release drawings while the product-design gates for the claimed maturity are unresolved.

Required Workflow

1. Classify maturity. Choose discovery, concept, design-development, engineering-candidate, or release-candidate. State what the requested output can and cannot prove.
2. Write the brief. Record users, scenarios, functions, critical actions, interfaces, environment, loads, anthropometry, size, cost, process, service, safety, appearance intent, retained features, prohibited features, and deliverables. Separate supplied, derived, assumed, contradictory, and TBD requirements.
3. Build architecture. Define functional blocks, energy/signal/material flows, purchased-component envelopes, motion axes, interfaces, assembly direction, cables/hoses, thermal paths, service volumes, and hazard keep-outs.
4. Generate concepts. For a new product or major redesign, compare at least three materially different architectures or silhouettes at the same scale. Color, fillet, or trim variants of one idea do not count.
5. Select and codify. Record the selected direction and why. Define primary/secondary/tertiary masses, control lines, section strategy, curvature/radius families, seams, openings, interface treatment, detail density, and CMF zones.
6. Pass the capability gate. Read cad-capability-contract.md. A primitive-only backend may prove packaging but may not claim refined surfaces, parametric assembly, or product rendering.
7. Create the skeleton. Model named overall dimensions, datums, component envelopes, support footprint, human contact zones, motion axes, interfaces, cable paths, thermal volumes, service access, and safety keep-outs. Preview immediately from common views.
8. Develop by subsystem. Add one logical feature or subsystem at a time. Read back actual feature identity, parameters, hierarchy, material role, bounds, and associations after each mutable stage. Roll back on unexplained mismatch.
9. Model configurations and motion. Use component instances and transforms, not duplicated loose geometry. Define fixed components, mates/limits, degrees of freedom, named configurations, motion envelopes, and interference evidence. See configuration-motion-render.md.
10. Review through separate channels. Judge design intent, ergonomics, architecture, geometry, motion, manufacturing, service, safety, and physical performance separately. A valid B-rep or attractive render is not an overall pass.
11. Handoff deliberately. Freeze the selected revision and configuration, list TBD and NOT_EVALUATED items, then invoke mechanical-drafting-gbt for manufacturing definition and release evidence.