ARCamera.TrackingState questions:
- Did the threshold or sensitivity for transitioning ARCamera.TrackingState from .normal to .limited(.excessiveMotion) or .limited(.insufficientFeatures) change between iOS 26.3 and iOS 26.4?
- What does "ARWorldTrackingTechnique: resource constraints [33]" mean, and is it new in iOS 26.4? Does it correspond to a tracking state degradation?
- Is there a way for the client to detect or respond to ARKit entering a resource-constrained mode short of the full tracking state transition — for example, a lower-level notification or a flag on ARFrame — so that apps can take protective action without interpreting it as a full tracking failure?
ARCamera.unprojectPoint questions:
- Did the behavior of ARCamera.unprojectPoint(_:ontoPlane:orientation:viewportSize:) change between iOS 26.3 and iOS 26.4 for near-parallel geometry? Specifically, on iOS 26.3 this method returns nil when the camera ray is nearly parallel to the target plane (denominator of the ray-plane intersection → 0 at ~90° of camera rotation). On iOS 26.4, with identical code and environment, it returns a large finite value instead — we observed z = −12.27m. Since the method's optional return type implies nil is the documented signal for no valid intersection, this reads as a behavioral regression rather than an intentional change.
- If returning the computed value for near-parallel geometry is now the intended behavior, is there a recommended way for the caller to guard against it? For example, should we check abs(dot(rayDirection, planeNormal)) against a threshold before calling, and if so, is there a documented epsilon Apple uses internally? Alternatively, is there a newer API we should prefer over unprojectPoint(:ontoPlane:) for this use case that handles degenerate geometry more gracefully — such as ARSession.raycast(:)?
Are there any other ARKit API adjustments between OS 26.3 and 26.4? We are using the same codebase, but it behaves differently in between these 2 OS versions now. Thanks!