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Framestore, this VR experience merges photoreal imagery with augmented elements using photogrammetry. https://www.framestore.com/work/saam-vr https://youtu.be/GHoS1ysjMG0?t=26
Try enabling this before you import a xref. The transforms need to be merged before you save the scene, or they will randomly move pos when you open after.
my guess is that they baked shadows into layer and then merge with final diffuse. Those baked shadows (+probably some of them were painted by hand) serve as mask too.
also, to avoid geometry overlapping, try to merge them manually, that can be a process of its own. And if this is used for game assets try to used well spaced quads