---
title: collisionImpulse
framework: scenekit
role: symbol
role_heading: Instance Property
path: scenekit/scnphysicscontact/collisionimpulse
---

# collisionImpulse

The force over time of the collision, in newton-seconds.

## Declaration

```swift
var collisionImpulse: CGFloat { get }
```

## Discussion

Discussion This property’s value tells you how hard the bodies struck each other in a collision. For example, in a game you might allow a character to proceed unhindered after a minor collision, but take damage when struck with sufficient force.

## See Also

### Inspecting the Contact Properties

- [nodeA](scenekit/scnphysicscontact/nodea.md)
- [nodeB](scenekit/scnphysicscontact/nodeb.md)
- [contactPoint](scenekit/scnphysicscontact/contactpoint.md)
- [contactNormal](scenekit/scnphysicscontact/contactnormal.md)
- [penetrationDistance](scenekit/scnphysicscontact/penetrationdistance.md)