---
title: collisionBoundingPath
framework: uikit
role: symbol
role_heading: Instance Property
path: uikit/uidynamicitem/collisionboundingpath
---

# collisionBoundingPath

The path-based shape to use for the collision bounds.

## Declaration

```swift
optional var collisionBoundingPath: UIBezierPath { get }
```

## Discussion

Discussion When the collisionBoundsType property is UIDynamicItemCollisionBoundsType.path, the object in this property is used as the collision bounds. If your dynamic item implements the collisionBoundsType property, you must also implement this property. The path object you create must represent a convex polygon with counter-clockwise or clockwise winding, and the path must not intersect itself. The (0, 0) point of the path must be located at the center point of the corresponding dynamic item. If the center point does not match the path’s origin, collision behaviors may not work as expected.

## See Also

### Participating in dynamic animation

- [bounds](uikit/uidynamicitem/bounds.md)
- [center](uikit/uidynamicitem/center.md)
- [transform](uikit/uidynamicitem/transform.md)
- [collisionBoundsType](uikit/uidynamicitem/collisionboundstype.md)