I’ve just followed this fat line tutorial from threejs examples
https://github.com/mrdoob/three.js/blob/master/examples/webgl_lines_fat.html#L105

However, when setting the code the line gets rendered as following:

    const newBox = mesh.geometry.clone();
    const edges = new THREE.EdgesGeometry(newBox);
    const lines = new THREE.LineSegments(
      edges,
      new THREE.LineBasicMaterial({ color: "red" })
    );
scene.add(lines);
    lines.applyMatrix4(mesh.matrix);
    lines.updateMatrix();

const pos = lines.geometry.attributes.position;
const geoLine = new LineGeometry();
    geoLine.setPositions(
      (pos.array as Float32Array).slice(0, 6)
    );

    const matLine = new LineMaterial({
      color: 0xffffff,
      linewidth: 1, // in world units with size attenuation, pixels otherwise
      vertexColors: false,
      dashed: false,
      alphaToCoverage: true,
    });
    const line = new Line2(geoLine, matLine);
    line.computeLineDistances();
    line.scale.set(1, 1, 1);
    scene.add(line);

what I said ………