---
title: CollisionEvents.Began
framework: realitykit
role: symbol
role_heading: Structure
path: realitykit/collisionevents/began
---

# CollisionEvents.Began

An event raised when two objects collide.

## Declaration

```swift
struct Began
```

## Topics

### Getting the involved entities

- [entityA](realitykit/collisionevents/began/entitya.md)
- [entityB](realitykit/collisionevents/began/entityb.md)

### Characterizing the collision

- [impulse](realitykit/collisionevents/began/impulse.md)
- [position](realitykit/collisionevents/began/position.md)

### Instance Properties

- [contacts](realitykit/collisionevents/began/contacts.md)
- [impulseDirection](realitykit/collisionevents/began/impulsedirection.md)
- [penetrationDistance](realitykit/collisionevents/began/penetrationdistance.md)

## Relationships

### Conforms To

- [Event](realitykit/event.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Detecting collisions

- [CollisionEvents.Updated](realitykit/collisionevents/updated.md)
- [CollisionEvents.Ended](realitykit/collisionevents/ended.md)