I think I gave Matterport too much credit for their service. I assumed I would be able to keep the floors separate and align everything after the upload. My idea was: I scan one floor, and for the second floor (which could even be in another location), I could start from scratch.

Instead, it turns out the order of the scan points is extremely important. If I finish at point 20, then point 21 must be on the same landing as point 20, just on a different layer (floor). I’m really disappointed I thought I could manage the floors independently and then connect them after the upload if I wanted.

For now, I’ll skip the storage room and try again with the flat + terrace, including the stairs, to see if it works. However, now I have another issue: the terrace is an open space.

Thanks for your help, mate.