<!-- SOLUV · part 196 -->
 P = new Vector3();

		// buffer

		const vertices = [];
		const normals = [];
		const uvs = [];
		const indices = [];

		// create buffer data

		generateBufferData();

		// build geometry

		this.setIndex( indices );
		this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
		this.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );
		this.setAttribute( 'uv', new Float32BufferAttribute( uvs, 2 ) );

		// functions

		function generateBufferData() {

			for ( let i = 0; i < tubularSegments; i ++ ) {

				generateSegment( i );

			}

			// if the geometry is not closed, generate the last row of vertices and normals
			// at the regular position on the given path
			//
			// if the geometry is closed, duplicate the first row of vertices and normals (uvs will differ)

			generateSegment( ( closed === false ) ? tubularSegments : 0 );

			// uvs are generated in a separate function.
			// this makes it easy compute correct values for closed geometries

			generateUVs();

			// finally create faces

			generateIndices();

		}

		function generateSegment( i ) {

			// we use getPointAt to sample evenly distributed points from the given path

			P = path.getPointAt( i / tubularSegments, P );

			// retrieve corresponding normal and binormal

			const N = frames.normals[ i ];
			const B = frames.binormals[ i ];

			// generate normals and vertices for the current segment

			for ( let j = 0; j <= radialSegments; j ++ ) {

				const v = j / radialSegments * Math.PI * 2;

				const sin = Math.sin( v );
				const cos = - Math.cos( v );

				// normal

				normal.x = ( cos * N.x + sin * B.x );
				normal.y = ( cos * N.y + sin * B.y );
				normal.z = ( cos * N.z + sin * B.z );
				normal.normalize();

				normals.push( normal.x, normal.y, normal.z );

				// vertex

				vertex.x = P.x + radius * normal.x;
				vertex.y = P.y + radius * normal.y;
				vertex.z = P.z + radius * normal.z;

				vertices.push( vertex.x, vertex.y, vertex.z );

			}

		}

		function generateIndices() {

			for ( let j = 1; j <= tubularSegments; j ++ ) {

				for ( let i = 1; i <= radialSegments; i ++ ) {

					const a = ( radialSegments + 1 ) * ( j - 1 ) + ( i - 1 );
					const b = ( radialSegments + 1 ) * j + ( i - 1 );
					const c = ( radialSegments + 1 ) * j + i;
					const d = ( radialSegments + 1 ) * ( j - 1 ) + i;

					// faces

					indices.push( a, b, d );
					indices.push( b, c, d );

				}

			}

		}

		function generateUVs() {

			for ( let i = 0; i <= tubularSegments; i ++ ) {

				for ( let j = 0; j <= radialSegments; j ++ ) {

					uv.x = i / tubularSegments;
					uv.y = j / radialSegments;

					uvs.push( uv.x, uv.y );

				}

			}

		}

	}

	copy( source ) {

		super.copy( source );

		this.parameters = Object.assign( {}, source.parameters );

		return this;

	}

	toJSON() {

		const data = super.toJSON();

		data.path = this.parameters.path.toJSON();

		return data;

	}

	/**
	 * Factory method for creating an instance of this class from the given
	 * JSON object.
	 *
	 * @param {Object} data - A JSON object representing the serialized geometry.
	 * @return {TubeGeometry} A new instance.
	 */
	static fromJSON( data ) {

		// This only works for built-in curves (e.g. CatmullRomCurve3).
		// User defined curves or instances of CurvePath will not be deserialized.
		return new TubeGeometry(
			new Curves[ data.path.type ]().fromJSON( data.path ),
			data.tubularSegments,
			data.radius,
			data.radialSegments,
			data.closed
		);

	}

}

/**
 * Can be used as a helper object to visualize a geometry as a wireframe.
 *
 * ```js
 * const geometry = new THREE.SphereGeometry();
 *
 * const wireframe = new THREE.WireframeGeometry( geometry );
 *
 * const line = new THREE.LineSegments( wireframe );
 * line.material.depthWrite = false;
 * line.material.opacity = 0.25;
 * line.material.transparent = true;
 *
 * scene.add( line );
 * ```
 *
 * Note: It is not yet possible to serialize/deserialize instances of this class.
 *
 * @augments BufferGeometry
 */
class WireframeGeometry extends BufferGeometry {

	/**
	 * Constructs a new wireframe geometry.
	 *
	 * @param {?BufferGeometry} [geometry=null] - The geometry.
	 */
	constructor( geometry = null ) {

		super();

		this.type = 'WireframeGeometry';

		/**
		 * Holds the constructor parameters that have been
		 * used to generate the geometry. Any modification
		 * after instantiation does not change the geometry.
		 *
		 * @type {Object}
		 */
		this.parameters = {
			geometry: geometry
		};

		if ( geometry !== null ) {

			// buffer

			const vertices = [];
			const edges = new Set();

			// helper variables

			const start = new Vector3();
			const end = new Vector3();

			if ( geometry.index !== null ) {

				// indexed BufferGeometry

				const position = geometry.attributes.position;
				const indices = geometry.index;
				let groups = geometry.groups;

				if ( groups.length === 0 ) {

					groups = [ { start: 0, count: