Thanks for the reply. So based on what you are saying if we add an ARAnchor for a camera pose position and then later ARKit refines using Loop closure & word map optimisation, will this refinement adjust the original value of the ARAnchor or not? What I am seeing is that the value is not changing. Is this correct behaviour or not? Thanks

Just an update. I just tried the as an experiment and the camera-pose ARAnchors were not refined. So basically they stayed the same as the original camera poses. Am I missing something? Are you confident that this approach should work? Thanks

Thanks, that is helpful. I just want to clarify one point so I understand the API correctly. If I create an ARAnchor using each frame's ARCamera.transform: let anchor = ARAnchor(transform: frame.camera.transform) session.add(anchor) is it correct that: The anchor initially represents the camera's world-space position and orientation at that frame; and If ARKit subsequently performs world-map refinement or loop closure, ARKit may change that anchor's transform, effectively giving me a refined historical camera pose; and There is no separate public API that lets me request the refined historical ARCamera.transform directly — using an ARAnchor in this way is the mechanism available to an app if it needs access to those refined poses? In other words, is the ARAnchor.transform after refinement effectively the public API for retrieving ARKit's updated version of that historical camera pose? Thanks — I just want to make sure I have understood your recommendation correctly.

Apologies for the late reply. Great detailed answer. We came to the same conclusion as the above. We are looking to solve the problem in a different way as a result