# SimulationMode

> A selection of modes that control when Unity executes the physics simulation.

## Definition

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

```csharp
public enum SimulationMode
```

## Remarks

Additional Resources: [Physics.simulationMode](/engine/6000.5/script-reference/unityengine/physics/simulationmode.md).

## Examples

```csharp
// SimulationMode.FixedUpdate is the default setting in Unity.
// Attach this script to a gameObject and enter runtime mode.

using UnityEngine;

public class ManualPhysicsSimulation : MonoBehaviour
{
    void Start()
    {
        Debug.Log("Current Physics.simulationMode: " + Physics.simulationMode);
    }
}
```

## Fields

| Value                                                                                    | Description                                                                                                                                                                                             |
| ---------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FixedUpdate](/engine/6000.5/script-reference/unityengine/simulationmode/fixedupdate.md) | Use this enumeration to instruct Unity to execute the physics simulation immediately after the [MonoBehaviour.FixedUpdate()](/engine/6000.5/script-reference/unityengine/monobehaviour/fixedupdate.md). |
| [Script](/engine/6000.5/script-reference/unityengine/simulationmode/script.md)           | Use this enumeration to instruct Unity to execute the physics simulation manually when you call [Physics.Simulate](/engine/6000.5/script-reference/unityengine/physics/simulate.md).                    |
| [Update](/engine/6000.5/script-reference/unityengine/simulationmode/update.md)           | Use this enumeration to instruct Unity to execute the physics simulation immediately after [MonoBehaviour.Update()](/engine/6000.5/script-reference/unityengine/monobehaviour/update.md).               |