Abstract: A multi-device system for mobile devices to acquire and share 3D maps of an environment. The mobile devices determine features of the environment and construct a local map and coordinate system for the features identified by the mobile device. The mobile devices may create a joint map by joining the local map of another mobile device or by merging the local maps created by the mobile devices. To merge maps, the coordinate system of each system may be constrained in degrees of freedom using information from sensors on the devices to determine the global position and orientation of each device. When the devices operate on a joint map, the device share information about new features to extend the range of features on the map and share information about augmented reality objects manipulated by users of each device.