[page:Geometry] →
# [name]

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.

## Code Example

```
const geometry = new THREE.CircleGeometry( 5, 32 );
const material = new THREE.MeshBasicMaterial( { color: 0xffff00 } );
const circle = new THREE.Mesh( geometry, material );
scene.add( circle );
```

## Constructor

### [name]([param:Float radius], [param:Integer segments], [param:Float thetaStart], [param:Float thetaLength])

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.

## Properties

See the base [page:Geometry] class for common properties.

### [property:Object parameters]

An object with a property for each of the constructor parameters. Any modification after instantiation does not change the geometry.

## Methods

See the base [page:Geometry] class for common methods.

## Source

[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]