1. An augmented reality system, comprising: a scanner to scan a space to provide a three-dimensional (3D) model of the space and people and objects within the space; a model store communicatively coupled to the scanner to store the 3D model and to store an augmented reality (AR) model, the AR model including placement constraints; a location identifier communicatively coupled to the model store to identify one or more candidate locations in the space for the AR model based on the 3D model, the AR model, and the placement constraints; a location ranker communicatively coupled to the location identifier to assign respective ranks to the one or more identified candidate locations based on placement ranking criteria; a location indicator communicatively coupled to the location ranker to indicate one or more of the identified candidate locations based on the assigned respective ranks; and a location selector communicatively coupled to the location ranker and the location indicator to select a placement location in the space for the AR model from the one or more identified candidate locations.