Sweep - OpenGeometry

OG_OPERATION_SWEEP moves a closed profile along a path. The parameters are { profile, path, caps? }. Both are wires.

Path	Result
Open polyline	Straight runs with mitred joints
`OG_PRIMITIVE_ARC`, or an open profile with arc segments	One exact bend per arc
Closed polyline, closed profile, or circle	A closed ring with no end faces

Place the profile across the start of the path. Its plane normal should point along the path.

A bend

The profile is a rectangle at the start of a quarter arc. The arc gives one exact bend with two cylindrical walls:

import {
  OpenGeometry,
  Solid,
  Wire,
  OG_OPERATION_SWEEP,
  OG_PRIMITIVE_ARC,
  OG_PRIMITIVE_PARAMS_ARC,
  OG_PRIMITIVE_RECTANGLE,
} from 'opengeometry';

await OpenGeometry.create(
  { wasmURL: '/opengeometry_bg.wasm' },
  { workerURL: '/tessellation-worker.js' },
);

const path = new Wire(
  OG_PRIMITIVE_ARC,
  OG_PRIMITIVE_PARAMS_ARC({ radius: 0.6, startAngle: 0, sweepAngle: Math.PI / 2 }),
);
const profile = new Wire(
  OG_PRIMITIVE_RECTANGLE,
  { width: 0.4, breadth: 0.25 },
  { plane: { origin: [0.6, 0, 0], normal: [0, 0, -1], xDirection: [1, 0, 0] } },
);
const duct = new Solid(OG_OPERATION_SWEEP, { profile, path });
console.log(duct.getBrep().topology.faces.length);

This prints 6. A circle profile on the same path gives torus faces: a pipe elbow.

An open sheet

With caps: false the ends stay open. The result has no volume, so it is a Sheet:

import {
  OpenGeometry,
  Sheet,
  Wire,
  OG_OPERATION_PARAMS_SWEEP,
  OG_OPERATION_SWEEP,
  OG_PRIMITIVE_POLYLINE,
  OG_PRIMITIVE_RECTANGLE,
} from 'opengeometry';

await OpenGeometry.create(
  { wasmURL: '/opengeometry_bg.wasm' },
  { workerURL: '/tessellation-worker.js' },
);

const profile = new Wire(OG_PRIMITIVE_RECTANGLE, { width: 0.7, breadth: 0.4 });
const path = new Wire(OG_PRIMITIVE_POLYLINE, {
  points: [
    [0, 0, 0],
    [0, 3, 0],
    [3, 3, 0],
  ],
});
const duct = new Sheet(
  OG_OPERATION_SWEEP,
  OG_OPERATION_PARAMS_SWEEP({ profile, path, caps: false }),
);
console.log(duct.bodyType, duct.getBrep().topology.faces.length);

This prints Sheet 8: eight side faces and no end faces. A sheet shows its surface from the front only. STEP export refuses it, and Sheet has no operate.

Rules

caps is true when you leave it out.
An arc in an open profile path should meet its lines tangentially.
A sweep that would cut through itself throws SweepSelfIntersection.
new Solid with caps: false, or new Sheet without it, throws BodyTypeMismatch.

​A bend

​An open sheet

​Rules

A bend

An open sheet

Rules