---
title: backfaceCulling
framework: scenekit
role: symbol
role_heading: Type Property
path: scenekit/scnphysicsworld/testoption/backfaceculling
---

# backfaceCulling

The key for choosing whether to ignore back-facing polygons in physics shapes when searching for contacts.

## Declaration

```swift
static let backfaceCulling: SCNPhysicsWorld.TestOption
```

## Discussion

Discussion The value for this key is an NSNumber object containing a Boolean value. The default value is true, specifying that the search should only return contacts with the exterior surfaces of any physics shapes. Change the value to false to consider contacts with both interior and exterior surfaces. This key applies only to ray and convex sweep tests, and only to physics shapes created using the concavePolyhedron option.

## See Also

### Type Properties

- [collisionBitMask](scenekit/scnphysicsworld/testoption/collisionbitmask.md)
- [searchMode](scenekit/scnphysicsworld/testoption/searchmode.md)
- [SCNPhysicsWorld.TestSearchMode](scenekit/scnphysicsworld/testsearchmode.md)