Questions about RoomPlan, Room API, USDZ/STEP comparison, and extended spatial scanning

1. Can the RoomPlan or Room API load an existing USDZ room model and compare it in real time with a new live scan of the same space?

No, unfortunately this is not possible just with built-in methods.

1. Is Apple considering extending RoomPlan beyond indoor rooms, for example to scan outdoor areas, house exteriors, terrain, and simple building volumes with rough dimensions?
2. Will RoomPlan support multi-floor continuous scanning, custom object detection elements, and reliable export of the scanned result to USDZ for further CAD/BIM workflows?

We cannot comment on future plans. But this is valuable feedback. Please make sure to also file these requests via feedback assistant. As for detecting custom objects, iOS 27 now supports ML-based object tracking: https://developer.apple.com/documentation/visionos/implementing-object-tracking-in-your-app

1. Is it possible to create a real-time comparator between a reference object in USDZ or STEP format and a physical object being scanned live, so that deviations in geometry or dimensions can be detected during scanning?

On a Vision Pro you could run a SceneReconstructionProvider to obtain a mesh of the physical object and then you would have to implement your own comparison function against the USD's mesh.

The one feature which will be good and can be used on iPad and iPhone pro and vision pro would be on device Hardware acelerated comparator API and extend ScenerecostructionProvider to iPhone and iPad with lidars , second for custom ML (but can be also maked that you send object to detection to ai model in cloud which generate 3d model from lidar detection and paste in usdz file) yes is possible but this also need to be combine to have detection and also add to roomplan api geometry combine api end export custom detected object with simple api in swift this would be beneficial also for vision pro and for the end continuous scanning for multifloor floor where we have lobby with big stairs or angle sloops would be visionOS beneficial

And also tanks you for your answer