ARAnchor
An object that specifies the position and orientation of an item in the physical environment.
Declaration
class ARAnchorMentioned in
Overview
To track the static positions and orientations of real or virtual objects relative to the camera, create anchor objects and use the add(anchor:) method to add them to your AR session.
Some ARKit features automatically add special anchors to a session. World-tracking sessions can add ARPlaneAnchor, ARObjectAnchor, and ARImageAnchor objects if you enable the corresponding features; face-tracking sessions add ARFaceAnchor objects.
Subclassing Notes
In addition to creating your own ARAnchor instances to track the real-world positions of your virtual content, you can also subclass ARAnchor to associate custom data with anchors you create. Ensure that your anchor classes behave correctly when ARKit updates frames or saves and loads anchors in an ARWorldMap:
Anchor subclasses must fullfill the requirements of the ARAnchorCopying protocol. ARKit calls init(anchor:) (on a background thread) to copy instances of your anchor class from each ARFrame to the next. Your implementation of this initializer should copy the values of any custom properties your subclass adds.
Anchor subclasses must also adopt the NSSecureCoding protocol. Override encode(with:) and init(coder:) to save and restore the values your subclass’ custom properties when ARKit saves and loads them in a world map.
Anchors are considered equal based on their identifier property.
Only anchors that do not adopt ARTrackable are included when you save a world map.