# AddCircle(Vector2, float)

> Adds a circle shape ( PhysicsShapeType2D.Circle ) to the shape group.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine](/engine/6000.5/script-reference/unityengine.md)
* **Assembly:** UnityEngine.Physics2DModule

```csharp
public int AddCircle(Vector2 center, float radius)
```

### Parameters

**** (\[Vector2]\(/engine/6000.5/script-reference/unityengine/vector2)): The center point of the circle shape. This is analogous to [Collider2D.offset](/engine/6000.5/script-reference/unityengine/collider2d/offset.md).**** (\[float]\(https\://learn.microsoft.com/dotnet/api/system.single)): The radius of the circle defining a radius around the `center`. This is identical to [CircleCollider2D.radius](/engine/6000.5/script-reference/unityengine/circlecollider2d/radius.md).

### Returns

| Type                                                       | Description                                                                                                                                                                                                        |
| ---------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| [int](https://learn.microsoft.com/dotnet/api/system.int32) | Returns the shape index the shape was added to in the [PhysicsShapeGroup2D](/engine/6000.5/script-reference/unityengine/physicsshapegroup2d.md). This index is used as the main reference when retrieving a shape. |

### Remarks

A circle shape is comprised of a single vertex (center ) and a `radius` that extends around that vertex. This is the most memory efficient and fastest primitive to use in all use-cases.

**NOTE**: A circle forms a closed shape and does have an interior therefore its interior is detectable by physics queries etc.

### Examples

```csharp
using UnityEngine;
using UnityEngine.Assertions;

public class Example : MonoBehaviour
{
    void Start()
    {
        CreateShape();
        GetShapeFromCollider();
    }

    // Create a custom shape.
    void CreateShape()
    {
        // Create a shape group.
        var shapeGroup = new PhysicsShapeGroup2D();

        // Add a Circle.
        var shapeIndex = shapeGroup.AddCircle
            (
                center: new Vector2(-2f, 3f),
                radius: 1f
            );

        // Fetch the actual shape created.
        var physicsShape = shapeGroup.GetShape(shapeIndex);

        // Validate what we created.
        Assert.AreEqual(PhysicsShapeType2D.Circle, physicsShape.shapeType);
        Assert.AreApproximatelyEqual(1f, physicsShape.radius);
        Assert.AreEqual(1, physicsShape.vertexCount);
    }

    // Get a physics shape from a Collider.
    void GetShapeFromCollider()
    {
        // Fetch the collider.
        var collider = GetComponent<CircleCollider2D>();

        // If the collider is not active and enabled then we'll get no shapes.
        // Let's just quit if not.
        if (!collider.isActiveAndEnabled)
            return;

        // Configure the collider.
        collider.radius = 1f;

        // Create a shape group.
        var shapeGroup = new PhysicsShapeGroup2D();

        // Get the collider shapes.
        collider.GetShapes(shapeGroup);

        // Fetch the actual shape.
        var physicsShape = shapeGroup.GetShape(0);

        // Validate what we retrieved.
        Assert.AreEqual(PhysicsShapeType2D.Circle, physicsShape.shapeType);
        Assert.AreApproximatelyEqual(1f, physicsShape.radius);
        Assert.AreEqual(1, physicsShape.vertexCount);
    }
}
```