makeGizmos( tbCenter, tbRadius ) {

		const curve = new EllipseCurve( 0, 0, tbRadius, tbRadius );
		const points = curve.getPoints( this._curvePts );

		//geometry
		const curveGeometry = new BufferGeometry().setFromPoints( points );

		//material
		const curveMaterialX = new LineBasicMaterial( { color: 0xff8080, fog: false, transparent: true, opacity: 0.6 } );
		const curveMaterialY = new LineBasicMaterial( { color: 0x80ff80, fog: false, transparent: true, opacity: 0.6 } );
		const curveMaterialZ = new LineBasicMaterial( { color: 0x8080ff, fog: false, transparent: true, opacity: 0.6 } );

		//line
		const gizmoX = new Line( curveGeometry, curveMaterialX );
		const gizmoY = new Line( curveGeometry, curveMaterialY );
		const gizmoZ = new Line( curveGeometry, curveMaterialZ );

		const rotation = Math.PI * 0.5;
		gizmoX.rotation.x = rotation;
		gizmoY.rotation.y = rotation;


		//setting state
		this._gizmoMatrixState0.identity().setPosition( tbCenter );
		this._gizmoMatrixState.copy( this._gizmoMatrixState0 );

		if ( this.object.zoom !== 1 ) {

			//adapt gizmos size to camera zoom
			const size = 1 / this.object.zoom;
			this._scaleMatrix.makeScale( size, size, size );
			this._translationMatrix.makeTranslation( - tbCenter.x, - tbCenter.y, - tbCenter.z );

			this._gizmoMatrixState.premultiply( this._translationMatrix ).premultiply( this._scaleMatrix );
			this._translationMatrix.makeTranslation( tbCenter.x, tbCenter.y, tbCenter.z );
			this._gizmoMatrixState.premultiply( this._translationMatrix );

		}

		this._gizmoMatrixState.decompose( this._gizmos.position, this._gizmos.quaternion, this._gizmos.scale );

		//

		this._gizmos.traverse( function ( object ) {

			if ( object.isLine ) {

				object.geometry.dispose();
				object.material.dispose();

			}

		} );

		this._gizmos.clear();

		//

		this._gizmos.add( gizmoX );
		this._gizmos.add( gizmoY );
		this._gizmos.add( gizmoZ );

	}
Creates the rotation gizmos matching trackball center and radius.

@private
@param {Vector3} tbCenter - The trackball center.
@param {number} tbRadius - The trackball radius.