# collision

> Script interface for the CollisionModule of a Particle System.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine](/engine/6000.7/script-reference/unityengine.md)
* **Assembly:** UnityEngine.ParticleSystemModule

```csharp
public ParticleSystem.CollisionModule collision { get; }
```

### Remarks

This module allows particles to collide with a predefined list of planes, or with the 2D and 3D physics worlds.

Particle System modules do not need to be reassigned back to the system; they are interfaces and not independent objects.

### Examples

```csharp
using UnityEngine;
using System.Collections;

[RequireComponent(typeof(ParticleSystem))]
public class ExampleClass : MonoBehaviour {
    void Start() {
        ParticleSystem ps = GetComponent<ParticleSystem>();
        var coll = ps.collision;
        coll.enabled = true;
        coll.bounce = 0.5f;
    }
}
```