# simulationLayers

> The Rigidbody2D and Collider2D layers to simulate.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine](/engine/6000.0/script-reference/unityengine.md)
* **Assembly:** UnityEngine.Physics2DModule

```csharp
public static LayerMask simulationLayers { get; set; }
```

### Remarks

By default, [All Layers](/engine/6000.0/script-reference/unityengine/physics2d/alllayers.md) are simulated, however if you specify layers in this property then only the [Rigidbody2D](/engine/6000.0/script-reference/unityengine/rigidbody2d.md) on those layers will be simulated. Along with this, only contacts for [Collider2D](/engine/6000.0/script-reference/unityengine/collider2d.md) on the specified layer(s) will be handled. Finally, only [joints](/engine/6000.0/script-reference/unityengine/joint2d.md) or [effectors](/engine/6000.0/script-reference/unityengine/effector2d.md) on the specified layer(s) will be handled.

This property is only used when the [SimulationMode](/engine/6000.0/script-reference/unityengine/physics2d/simulationmode.md) is in one of the automatic simulation modes i.e. [SimulationMode2D.FixedUpdate](/engine/6000.0/script-reference/unityengine/simulationmode2d/fixedupdate.md) or [SimulationMode2D.Update](/engine/6000.0/script-reference/unityengine/simulationmode2d/update.md).  When using [SimulationMode2D.Script](/engine/6000.0/script-reference/unityengine/simulationmode2d/script.md) and calling [Physics2D.Simulate](/engine/6000.0/script-reference/unityengine/physics2d/simulate.md), the simulation layers are pass as an argument.

Additional Resources: [Physics2D.simulationMode](/engine/6000.0/script-reference/unityengine/physics2d/simulationmode.md) and [Physics2D.Simulate](/engine/6000.0/script-reference/unityengine/physics2d/simulate.md).