Composition

Build BREP models from JSON feature specifications or sheet-metal specs. Both verbs are JSON-driven (request on stdin or file path) and write a BREP output.

Entries

reconstruct · compose-sheet-metal

reconstruct

Build a BREP from a JSON [FeatureSpec] via FeatureReconstructor.

Input — JSON request on stdin or file path. Both forms supported.

Parameters

Feature kinds and fields — each feature entry has a kind discriminator:

• revolve — id (string), profile_points_2d (array of [x, y]), axis_origin ([x, y, z]), axis_direction ([x, y, z]), angle_deg (number)
• extrude — id, profile_points_2d, direction ([x, y, z]), length (number)
• hole — id, center ([x, y, z]), direction ([x, y, z]), radius (number), depth (number)
• thread — id, spec (string), hole_ref (string), length (number, optional)
• fillet — id, edges (array of edge IDs), radius (number)
• chamfer — id, edges, distance (number)

• boolean — id, op ("union"

  "subtract"

  "intersection"), left (string, often "@input"), right (string)

Returns — JSON object with:

• shape — path to output BREP file, or null if build failed
• fulfilled — array of feature IDs that succeeded

• skipped — array of objects with id, stage, reason (under_determined

  occt_failure

  unresolved_ref

  unsupported), and optional detail

• annotations — array of objects with id, kind ("thread"), and optional detail

Example

cat > /tmp/revolve.json <<'EOF'
{
  "outputDir": "/tmp/out",
  "outputName": "shaft",
  "features": [
    {
      "kind": "revolve",
      "id": "shaft",
      "profile_points_2d": [[0,0], [10,0], [10,40], [0,40]],
      "axis_origin": [0,0,0],
      "axis_direction": [0,0,1],
      "angle_deg": 360
    }
  ]
}
EOF
reconstruct /tmp/revolve.json

{
  "shape": "/tmp/out/shaft.brep",
  "fulfilled": ["shaft"],
  "skipped": [],
  "annotations": []
}

Drives — OCCTSwift.FeatureReconstructor.buildJSON(_:inputBody:) (v0.147+; inputBody: parameter added v0.152; boolean JSON decoder branch added v0.152.1).

Notes — When inputBrep is supplied, hole/fillet/chamfer entries cut/finish the loaded body directly; additive features (extrude/revolve) union onto it. Use {"kind":"boolean","op":"subtract","left":"@input","right":<id>} entries to express non-circular pocket cuts that reference the seeded body.

compose-sheet-metal

Compose a sheet-metal BREP from a JSON spec via SheetMetal.Builder.

Input — JSON request on stdin or file path. Both forms supported.

Parameters

Returns — JSON object with:

• shape — absolute path to output BREP file
• flanges — count of flanges composed
• bends — count of bends applied

Example

cat > /tmp/channel.json <<'EOF'
{
  "outputDir": "/tmp/out",
  "outputName": "u_channel",
  "thickness": 2.0,
  "flanges": [
    {
      "id": "base",
      "profile": [[0,0], [100,0], [100,50], [0,50]],
      "origin": [0,0,0],
      "uAxis": [1,0,0],
      "normal": [0,0,1]
    },
    {
      "id": "left_wall",
      "profile": [[0,0], [0,50], [25,50], [25,0]],
      "origin": [0,0,0],
      "uAxis": [0,1,0],
      "normal": [-1,0,0]
    }
  ],
  "bends": [
    {"from": "base", "to": "left_wall", "radius": 2.0}
  ]
}
EOF
compose-sheet-metal /tmp/channel.json

{
  "shape": "/tmp/out/u_channel.brep",
  "flanges": 2,
  "bends": 1
}

Drives — OCCTSwift.SheetMetal.Builder(thickness:).build(flanges:bends:) (v0.151+; bend step awareness added v0.153).

Notes — Kept separate from reconstruct because SheetMetal lives in its own upstream namespace. The split also reserves room for the planned reverse direction (bent BREP → flat cutting pattern).