constructor() {

		super( 'layouter', null, false);

		// configure
		this._needsUpdate = true;

		/**
		 * @typedef ChildrenPos
		 * @type {Object & Object.<string,Vector3>}
		 */

		/**
		 *
		 * @type {ChildrenPos}
		 * @internal
		 */
		this._childrenPos = {};

	}
The vertical position of this line
@type {number}