CircleGeometry is a simple shape of Euclidean geometry. It is contructed from a number of triangular segments that are oriented around a central point and extend as far out as a given radius. It is built counter-clockwise from a start angle and a given central angle. It can also be used to create regular polygons, where the number of segments determines the number of sides.
		var geometry = new THREE.CircleGeometry( 5, 32 );
		var material = new THREE.MeshBasicMaterial( { color: 0xffff00 } );
		var circle = new THREE.Mesh( geometry, material );
		scene.add( circle );
		
		
		radius — Radius of the circle, default = 1.
		segments — Number of segments (triangles), minimum = 3, default = 8.
		thetaStart — Start angle for first segment, default = 0 (three o'clock position).
		thetaLength — The central angle, often called theta, of the circular sector. The default is 2*Pi, which makes for a complete circle.
		
See the base [page:Geometry] class for common properties.
An object with a property for each of the constructor parameters. Any modification after instantiation does not change the geometry.
See the base [page:Geometry] class for common methods.
[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]