A room manager can generate mappings for a real-world room that support a shared XR environment. For example, the real-world room can include real-world objects and surfaces, such as a table(s), chair(s), wall(s), door(s), window(s), etc. The room manager can generate XR object definitions based on information received about the real-world room, object(s), and surface(s). For example, the room manager can implement a flow that guides a user equipped with an XR system to provide information for the XR object definitions, such as real-world surfaces that map to the XR object(s), borders (e.g., measured using a component of the XR system), such as borders on real-world surfaces, semantic information (e.g., number of seat assignments at an XR table, size of XR objects, etc.), and other suitable information. Implementations generate previews of the shared XR environment, such as a local preview and a remote preview.