In my experience, the building information is passed from Open Street Map, especially where there is no photogrammetry in the sim. This is the case for Covington and Monroe. Corona has buildings, but they may have been added after the information was pulled into the sim. I don’t know how often OSM data is refreshed in the sim. It appears to be used for road traffic, light generation at night (except for airports), and building height in non photogrammetric locations. I will try to put the building footprints into OSM then submit a Zendesk ticket for missing buildings.