Through testing we've identified a weird issue with the quest 2. As per my understanding, 1 unreal unit = 1 cm, so a 9 meter wide square should be 900 units wide. In testing this setup, we've observed the following:
We have a calibration method that lines up the virtual world with the real world around the green circle. We've verified this works by observing and checking it after calibration and trust that it is lined up properly. As we begin moving around with multiple users by the green circle, players physically are in sync with their virtual avatars. However as we approach the red circle, we become incredibly out of sync as much as 40-50cm offset. As we return to the green circle we come in sync again. We have a local multiplayer server that we run to share location. As we're only moving around via real world walking, we have no movement component.
After aligning the the virtual worlds, all players virtual worlds would be in sync. So we simply have the client report their world position to the server (HMD and controllers) who then multicasts that out to the other clients. There is no gameplay here, and this is only used locally, so there is no security or gameplay concerns.
What does concern us is this weird elliptical offset. If you walk around the space in a circle as you approach the red circle you become more and more out of sync until you start coming back then become more and more in sync. We've verified the syncing of the virtual world to the real world, so this doesn't appear to be a case of a twisted virtual world simply throwing off the positioning.
Any thoughts on what might be causing this? It doesn't feel like a tracking issue, because as we move around the circle repeatedly we always end up in sync when we come back. if there was a general tracking issue, I'd expect that we'd be totally out of sync when we got back around.