				generateGeometry();

				},

				CircleGeometry: function ( mesh ) {

					const data = {
						radius: 10,
						segments: 32,
						thetaStart: 0,
						thetaLength: twoPi
					};

					function generateGeometry() {

						updateGroupGeometry( mesh,
							new CircleGeometry(
								data.radius, data.segments, data.thetaStart, data.thetaLength
							)
						);

					}

					const folder = gui.addFolder( 'THREE.CircleGeometry' );

					folder.add( data, 'radius', 1, 20 ).onChange( generateGeometry );