Nice, ill have into that… ARKit 2 has a shared exp type of system, not sure though how they are doing it, most of the demos I saw where inside, and they probably create some sort of blutooth connection between devices to provide location…
I know Unreal has the ability on the iPhone to enable location detection… just need to figure out how to store that with the objects location and save that to a mongo db… then when the user launches the app it queries the db for give me anything $near lat/long with min/max distance… then display that… however items could be stick in trees etc…