The key for selecting which categories of physics bodies that SceneKit should test for contacts.
- iOS 8.0+
- macOS 10.10+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
The value for this key is an
NSNumber object containing an
NSUInteger value. SceneKit tests for contacts only with physics bodies whose
category property overlaps with this bit mask. The default value is
all, specifying that searches should test all physics bodies regardless of their category.