<!-- NEW2 — TEST 2 · THE DISTRICT OF 800 · part 100 -->
angle index.
	 * @param {number} count - Specifies how many vertices (or indices) are part of this group.
	 * @param {number} [materialIndex=0] - The material array index to use.
	 */
	addGroup( start, count, materialIndex = 0 ) {

		this.groups.push( {

			start: start,
			count: count,
			materialIndex: materialIndex

		} );

	}

	/**
	 * Clears all groups.
	 */
	clearGroups() {

		this.groups = [];

	}

	/**
	 * Sets the draw range for this geometry.
	 *
	 * @param {number} start - The first vertex for non-indexed geometry, otherwise the first triangle index.
	 * @param {number} count - For non-indexed BufferGeometry, `count` is the number of vertices to render.
	 * For indexed BufferGeometry, `count` is the number of indices to render.
	 */
	setDrawRange( start, count ) {

		this.drawRange.start = start;
		this.drawRange.count = count;

	}

	/**
	 * Applies the given 4x4 transformation matrix to the geometry.
	 *
	 * @param {Matrix4} matrix - The matrix to apply.
	 * @return {BufferGeometry} A reference to this instance.
	 */
	applyMatrix4( matrix ) {

		const position = this.attributes.position;

		if ( position !== undefined ) {

			position.applyMatrix4( matrix );

			position.needsUpdate = true;

		}

		const normal = this.attributes.normal;

		if ( normal !== undefined ) {

			const normalMatrix = new Matrix3().getNormalMatrix( matrix );

			normal.applyNormalMatrix( normalMatrix );

			normal.needsUpdate = true;

		}

		const tangent = this.attributes.tangent;

		if ( tangent !== undefined ) {

			tangent.transformDirection( matrix );

			tangent.needsUpdate = true;

		}

		if ( this.boundingBox !== null ) {

			this.computeBoundingBox();

		}

		if ( this.boundingSphere !== null ) {

			this.computeBoundingSphere();

		}

		this._transformed = true;

		return this;

	}

	/**
	 * Applies the rotation represented by the Quaternion to the geometry.
	 *
	 * @param {Quaternion} q - The Quaternion to apply.
	 * @return {BufferGeometry} A reference to this instance.
	 */
	applyQuaternion( q ) {

		_m1.makeRotationFromQuaternion( q );

		this.applyMatrix4( _m1 );

		return this;

	}

	/**
	 * Rotates the geometry about the X axis. This is typically done as a one time
	 * operation, and not during a loop. Use {@link Object3D#rotation} for typical
	 * real-time mesh rotation.
	 *
	 * @param {number} angle - The angle in radians.
	 * @return {BufferGeometry} A reference to this instance.
	 */
	rotateX( angle ) {

		// rotate geometry around world x-axis

		_m1.makeRotationX( angle );

		this.applyMatrix4( _m1 );

		return this;

	}

	/**
	 * Rotates the geometry about the Y axis. This is typically done as a one time
	 * operation, and not during a loop. Use {@link Object3D#rotation} for typical
	 * real-time mesh rotation.
	 *
	 * @param {number} angle - The angle in radians.
	 * @return {BufferGeometry} A reference to this instance.
	 */
	rotateY( angle ) {

		// rotate geometry around world y-axis

		_m1.makeRotationY( angle );

		this.applyMatrix4( _m1 );

		return this;

	}

	/**
	 * Rotates the geometry about the Z axis. This is typically done as a one time
	 * operation, and not during a loop. Use {@link Object3D#rotation} for typical
	 * real-time mesh rotation.
	 *
	 * @param {number} angle - The angle in radians.
	 * @return {BufferGeometry} A reference to this instance.
	 */
	rotateZ( angle ) {

		// rotate geometry around world z-axis

		_m1.makeRotationZ( angle );

		this.applyMatrix4( _m1 );

		return this;

	}

	/**
	 * Translates the geometry. This is typically done as a one time
	 * operation, and not during a loop. Use {@link Object3D#position} for typical
	 * real-time mesh rotation.
	 *
	 * @param {number} x - The x offset.
	 * @param {number} y - The y offset.
	 * @param {number} z - The z offset.
	 * @return {BufferGeometry} A reference to this instance.
	 */
	translate( x, y, z ) {

		// translate geometry

		_m1.makeTranslation( x, y, z );

		this.applyMatrix4( _m1 );

		return this;

	}

	/**
	 * Scales the geometry. This is typically done as a one time
	 * operation, and not during a loop. Use {@link Object3D#scale} for typical
	 * real-time mesh rotation.
	 *
	 * @param {number} x - The x scale.
	 * @param {number} y - The y scale.
	 * @param {number} z - The z scale.
	 * @return {BufferGeometry} A reference to this instance.
	 */
	scale( x, y, z ) {

		// scale geometry

		_m1.makeScale( x, y, z );

		this.applyMatrix4( _m1 );

		return this;

	}

	/**
	 * Rotates the geometry to face a point in 3D space. This is typically done as a one time
	 * operation, and not during a loop. Use {@link Object3D#lookAt} for typical
	 * real-time mesh rotation.
	 *
	 * @param {Vector3} vector - The target point.
	 * @return {BufferGeometry} A reference to this instance.
	 */
	lookAt( vector ) {

		_obj.lookAt( vector );

		_obj.updateMatrix();

		this.applyMatrix4( _obj.matrix );

		return this;

	}

	/**
	 * Center the geometry based on