US Patent 10957112 Cross reality system

An augmented reality viewing system is described. A local coordinate frame of local content is transformed to a world coordinate frame. A further transformation is made to a head coordinate frame and a further transformation is made to a camera coordinate frame that includes all pupil positions of an eye. One or more users may interact in separate sessions with a viewing system. If a canonical map is available, the earlier map is downloaded onto a viewing device of a user. The viewing device then generates another map and localizes the subsequent map to the canonical map.