Cadquery Part Detailing

CadQuery part detailing — geometric finish pass

Purpose

Make the part look and behave like engineered hardware: ribs, gussets, stress-relief fillets, hole lead-ins, rounded plate outlines. The functional solid from cadquery-part must already assemble and interference-check clean before this pass.

What this pass is NOT

If functional geometry is missing a rib required for strength, add it here — but do not add mounting holes.

Authoritative rules

cad-generation.txt — Design Realism, Edge Selectors, fillets/chamfers last, sketch-level fillets when possible.

Inputs

• parts/<function_name>.py after functional pass + local interference OK
• Mechanical role: cantilevered walls, handled edges, molded corners
• Mating direction (usually +Z) for lead-in chamfers

Build order — strict

1. Re-open the functional file — preserve parameters and functional block; append a # ---- Detailing ---- section.
2. Structural reinforcement (single-extrusion union each):
   • Ribs / gussets on cantilevers: polyline(...).close().extrude(t)
   • Boss pads only where functional pass left thin material around an existing hole — do not re-drill
3. Lead-in chamfers on existing hole entries and spigot leads — small (0.3–0.8 mm), 1–2 string selectors
4. Fillets last — inside corners first, then external ergonomics; radius ≤ 40% of local wall thickness
5. Sketch-level rounding for plate outlines when the whole perimeter should be round:

plate = (
    cq.Workplane("XY")
    .sketch().rect(w, h).vertices().fillet(r).finalize()
    .extrude(t)
)

Prefer sketch-level for plate corners — post-extrusion edges(">Z") often fails silently.

6. result = build_<function_name>() — update the builder to return the detailed body, not a orphan variable.

Template (append inside build_*())

    # ---- Detailing: reinforcement ----
    gusset = (
        cq.Workplane("XZ", origin=(gx, 0, gz))
        .polyline([(0, 0), (rib_l, 0), (0, rib_h)]).close()
        .extrude(rib_t)
    )
    part = part.union(gusset)

    # ---- Detailing: lead-in chamfers (holes face +Z) ----
    part = part.edges("|Z").edges(">Z").chamfer(0.5)

    # ---- Detailing: fillets (inside corners) ----
    part = part.edges("|Z").fillet(1.5)

    return part

Anti-patterns

• Fillets before all unions/cuts in this section complete
• cq.selectors.*
• Fillet radius > local thickness
• Duplicating ribs/bosses already in functional pass
• New cut() features except tiny lead-in chamfers on existing geometry

Validation

Orchestrator runs cadquery-render then compares to functional renders:

• Sharp edge where fillet expected → selector failed; tighten (|Z + >X) or use sketch fillet
• New clash with neighbor → reposition rib or hand to interference skill

Re-run local cadquery-interference-check after detailing — ribs often cause clashes.

Output

Same file parts/<function_name>.py, same build_<function_name>(), with detailing inside the builder. Top-level result = build_<function_name>().