1. A method, comprising: receiving, from a three-dimensional vision sensor of a robot, a group of data points sensed by the three-dimensional vision sensor; retrieving, by one or more processors, a three-dimensional planar model that approximates a plurality of surfaces of an object, the planar model defining a plurality of planar shapes modeled relative to one another in a three-dimensional space, wherein the object is a pallet that includes a plurality of stringers and wherein a first planar shape of the planar model approximates a first stringer surface of a first stringer end of a first stringer of the stringers and a second planar shape of the planar model approximates a second stringer surface of a second stringer end of a second stringer of the stringers, and wherein the first stringer end and the second stringer end are both on a same side of the pallet; calculating, by one or more of the processors and for each of a plurality of projections of the model to the data points, differences between the planar model and the data points for a corresponding projection of the projections; determining, by one or more of the processors, that a projection of the projections satisfies a threshold based on the differences between the planar model and the data points for the projection; and determining, by one or more of the processors, an object pose for the object relative to the robot based on a planar model pose of the planar model at the projection that satisfies the threshold.