# Sandbox.Animation.GraphBuilder.TwoBoneIK

```csharp
Node TwoBoneIK(Node child, string effectorBone, Node target, TwoBoneIKSettings settings = null)
```

Analytical two bone IK - rotates the effector bone's two parents (e.g.
shoulder and elbow) so the effector reaches the target, and aligns the
effector to the target's rotation.

### Parameters

- `child` (`Node`): Pose to apply the IK on top of.
- `effectorBone` (`string`): The end bone of the IK chain, e.g. `"hand_R"`.
- `target` (`Node`): Target node providing the effector target transform, e.g. a [Sandbox.Animation.GraphBuilder.TargetParameter](/api/Sandbox.Animation.GraphBuilder/TargetParameter).
- `settings` (`TwoBoneIKSettings`), default `null`: IK blending and targeting options.

### Returns

`Node`

Declared in [Sandbox.Animation.GraphBuilder](/api/Sandbox.Animation.GraphBuilder).
Assembly: `Sandbox.Engine`.