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# CollisionEvents.Began

An event raised when two objects collide.

```
struct Began
```

## Topics

### Getting the involved entities

[`entityA`](/documentation/RealityKit/CollisionEvents/Began/entityA)

The first entity involved in the collision.

[`entityB`](/documentation/RealityKit/CollisionEvents/Began/entityB)

The second entity involved in the collision.

### Characterizing the collision

[`impulse`](/documentation/RealityKit/CollisionEvents/Began/impulse)

The total impulse in this collision pair obtained by adding up all the
individual impulses applied at each contact point.

[`position`](/documentation/RealityKit/CollisionEvents/Began/position)

A position representing the estimated point of contact.

## Relationships

### Conforms To

[`Event`](/documentation/RealityKit/Event)

[`Sendable`](/documentation/Swift/Sendable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

---

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