updateWorldMatrix( updateParents, updateChildren ) {

		const parent = this.parent;

		if ( updateParents === true && parent !== null ) {

			parent.updateWorldMatrix( true, false );

		}

		if ( this.matrixAutoUpdate ) this.updateMatrix();

		if ( this.matrixWorldAutoUpdate === true ) {

			if ( this.parent === null ) {

				this.matrixWorld.copy( this.matrix );

			} else {

				this.matrixWorld.multiplyMatrices( this.parent.matrixWorld, this.matrix );

			}

		}

		// make sure descendants are updated

		if ( updateChildren === true ) {

			const children = this.children;

			for ( let i = 0, l = children.length; i < l; i ++ ) {

				const child = children[ i ];

				child.updateWorldMatrix( false, true );

			}

		}

	}
An alternative version of {@link Object3D#updateMatrixWorld} with more control over the
update of ancestor and descendant nodes.

@param {boolean} [updateParents=false] Whether ancestor nodes should be updated or not.
@param {boolean} [updateChildren=false] Whether descendant nodes should be updated or not.