name: onshape-featurescript description">Generate Onshape FeatureScript code for custom CAD features and parametric parts. Specializes in dust collection fittings library (wyes, elbows, adapters, crosses). Use when user asks to: (1) create FS features (gears, fittings, brushes), (2) modify existing FS, (3) debug FS errors, (4) build libraries with consistent patterns (enums, shells, labels). Patterns for Z-axis fittings, wrapped labels, safe unions/shells. Triggers: 'Onshape FS for X', 'FeatureScript wye/elbow', 'dust fitting'.</description>

Onshape FeatureScript Generator

Quick Start

Analyze request → Match pattern → Gen FS code → Validate logic.

Core Workflow:

1. Precondition: Enums/lengths/reals w/ bounds.
2. Body: Sketches → Extrudes → Booleans → Shell → Wrap/Thicken labels.
3. Pitfalls: qOwnedByBody(finalBody), if/else (no ternary lengths), cylinder(coordSystem).

Key Patterns (Memorize)

• Enum + Cond Param:

  export enum AlignmentStyle { Centered, Tangent, Offset };
  if (definition.alignment == AlignmentStyle.Offset) { isLength(def.offsetDistance...); }
  

• Safe Shell Caps:

  var capFaces = qFacesParallelToDirection(qOwnedByBody(finalBody, EntityType.FACE), vector(0,1,0));
  

• Union Primary First:

  qUnion([qCreatedBy(id+"inlet", EntityType.BODY), ...]);
  

• Wrapped Label: skText → opWrap → opThicken.

Dust Fittings Lib

Z-axis: Inlet Z=0 (-Z), Outlet Z=trans (+Z), Branch +X. See FITTINGS.md for full spec/pitfalls.

Resources

• API Patterns: PATTERNS.md
• Fonts: AllertaStencil-Regular.ttf for labels.
• Validate: Test mentally; no runtime here.

Gen code → User pastes to Onshape FS editor.