OCCT Fillets: Applying to 2D Wires

Filleting operations in OpenCascade Technology (OCCT) are not limited to 3D solids and shells; they can also be effectively applied to 2D wires to create rounded corners where two or more edges meet. This is useful for smoothing out polygonal paths or creating more organic 2D profiles that can later be used for operations like extrusions or lofts.

Similar to filleting solids, you can typically:

1. Apply a fillet with a uniform radius to all eligible corners (vertices where edges connect) of a wire.
2. Apply fillets with potentially different radii to specific corners of the wire, usually by referencing the vertices at those corners.

Filleting All Corners of a Wire (Uniform Radius)

The examples below demonstrate how to create a simple 2D wire (e.g., a polyline or a rectangle) and then apply a fillet with the same radius to all of its corners.

TypeScript Example: Fillet All Corners of a Wire

Fillet All Corners of Wire

Typescript

Script Source (typescript)

const start = async () => {
    const squareOpt = new Bit.Inputs.OCCT.SquareDto();
    const square = await bitbybit.occt.shapes.wire.createSquareWire(squareOpt);
    const squareFillet = await bitbybit.occt.fillets.fillet2d({
        shape: square,
        radius: 0.25
    });

    bitbybit.draw.drawAnyAsync({
        entity: squareFillet
    });
}

start();

Blockly Example: Fillet All Corners of a Wire

Fillet All Corners of Wire

Blockly

Script Source (blockly)

<xml xmlns="https://developers.google.com/blockly/xml"><block type="bitbybit.draw.drawAnyAsyncNoReturn" id="UO^K1-FNciNjT{DsaF2S" x="112" y="-911"><value name="Entity"><block type="bitbybit.occt.fillets.fillet2d" id="C9O)i|qmEJgLap43-Z;L"><value name="Shape"><block type="bitbybit.occt.shapes.wire.createSquareWire" id="H3^18TfO9slzrT21aztx"><value name="Size"><block type="math_number" id="^LeJ!`3jIgdZDn}p=/bh"><field name="NUM">1</field></block></value><value name="Center"><block type="bitbybit.point.pointXYZ" id="mzmQQh/*F|$K,Yc?3.}k"><value name="X"><block type="math_number" id="oh:NburJx[a!Ofti2S.Y"><field name="NUM">0</field></block></value><value name="Y"><block type="math_number" id="VYEX8LF=Ou3uq3A,N6GT"><field name="NUM">0</field></block></value><value name="Z"><block type="math_number" id="%Wf,`I{_m0gkmBbNqB1W"><field name="NUM">0</field></block></value></block></value><value name="Direction"><block type="bitbybit.vector.vectorXYZ" id="l0hSQuR6ry``rvJ9QHk3"><value name="X"><block type="math_number" id="o4=QGwqlf{--K1gP)M#M"><field name="NUM">0</field></block></value><value name="Y"><block type="math_number" id="}yFeDDSKT_@.{16TJ{/u"><field name="NUM">1</field></block></value><value name="Z"><block type="math_number" id="SBLFXbbDZxZ,T+!5$[dh"><field name="NUM">0</field></block></value></block></value></block></value><value name="Radius"><block type="math_number" id="M!i:8)[8Bg_8_~nA)0Br"><field name="NUM">0.24</field></block></value></block></value></block></xml>

Rete Example: Fillet All Corners of a Wire

Fillet All Corners of Wire

Rete

Script Source (rete)

{
  "id": "rete-v2-json",
  "nodes": {
    "2978b0692166de48": {
      "id": "2978b0692166de48",
      "name": "bitbybit.occt.shapes.wire.createSquareWire",
      "customName": "square wire",
      "async": true,
      "drawable": true,
      "data": {
        "genericNodeData": {
          "hide": true,
          "oneOnOne": false,
          "flatten": 0,
          "forceExecution": false
        },
        "size": 1,
        "center": [
          0,
          0,
          0
        ],
        "direction": [
          0,
          1,
          0
        ]
      },
      "inputs": {},
      "position": [
        791.154487937843,
        877.3944151133886
      ]
    },
    "f4d42f035c26c026": {
      "id": "f4d42f035c26c026",
      "name": "bitbybit.occt.fillets.fillet2d",
      "customName": "fillet 2d",
      "async": true,
      "drawable": true,
      "data": {
        "genericNodeData": {
          "hide": false,
          "oneOnOne": false,
          "flatten": 0,
          "forceExecution": false
        },
        "radius": 0.24
      },
      "inputs": {
        "shape": {
          "connections": [
            {
              "node": "2978b0692166de48",
              "output": "result",
              "data": {}
            }
          ]
        }
      },
      "position": [
        1249.5551047178622,
        873.9058590672774
      ]
    }
  }
}

Applying fillets to 2D wires is a common technique for refining profiles before they are used to generate more complex 3D shapes, ensuring smooth and continuous transitions in the final model.