[page:Line] →
		[name]
		Renders [page:ArrowHelper arrows] to visualize an object's [page:Face3 face] normals. Requires that the object's geometry be an instance of [page:Geometry] (does not work with [page:BufferGeometry]), and that face normals have been specified on all [page:Face3 faces] or calculated with [page:Geometry.computeFaceNormals computeFaceNormals].
		Example
		
		geometry = new THREE.BoxGeometry( 10, 10, 10, 2, 2, 2 );
		material = new THREE.MeshBasicMaterial( { color: 0xff0000 } );
		object = new THREE.Mesh( geometry, material );
		edges = new THREE.FaceNormalsHelper( object, 2, 0x00ff00, 1 );
		scene.add( object );
		scene.add( edges );
		
		[example:webgl_helpers Example using various helpers]
		Constructor
		[name]( [page:Object3D object], [page:Number size], [page:Color color], [page:Number linewidth] )
		
		object -- object for which to render face normals
		size -- size (length) of the arrows
		color -- color of the arrows
		linewidth -- width of the arrow lines
		
		Properties
		[property:Object3D object]
		
		The attached object
		
		Methods
		[method:null update]()
		Updates the face normal preview based on movement of the object.
		Source
		[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]