https://placenote.com/ provides a software and service for registration of 3D scenes in AR: https://vertical.ai/.
To put it simply, Placenote lets you build AR apps that permanently place augmented reality content in precise locations, indoors and outdoors. Placenote does not need GPS, markers or beacons for geolocation. Instead, it uses an advanced computer vision system to provide an additional layer of mapping and persistent visual positioning to mobile AR apps built in Unity or Native Scenekit.
I have registered and built the example by using their kit.
The sample allows you to position objects in a AR session and save the map to their service. Then in a consecutive AR session you can load the saved map again. The sample seems to work pretty well and successfully re-positions the objects. The accuracy is not very high, objects can be a bit off the intended position. If the starting position is very different (other side of a room) it doesn’t place the objects.
The source code of the sample is also available on github https://github.com/Placenote.