1. A method performed by a processor comprising: receiving, at the processor, image depth data, wherein the image depth data includes depth data of a subject to be modeled; locating a trunk of the subject from the image depth data, and creating a three-dimensional (3D) model of the trunk of the subject; locating a head of the subject using the 3D model of the trunk and the image depth data, and creating a 3D model of the head of the subject; using the 3D models of the trunk and the head of the subject to remove a subset of data from the image depth data corresponding to the trunk and the head of the subject; and using remaining image depth data to locate an extremity of the subject, wherein the 3D model of the trunk of the subject is a parametric cylinder model, and further wherein parameters of a cylinder of the parametric cylinder model are determined using a least-squares approximation based on the image depth data corresponding to the trunk of the subject.