1. A method of dynamically targeting an arbitrary rest position for finite elements representing an object structure in an image, the method comprising: a) receiving, at one or more computer systems, information defining an initial mesh representation representing an initial pose of an object in a first image frame; b) receiving, at the one or more computer systems, information defining a configuration of finite elements representing a rest state of an interior structure of the initial mesh representation; c) receiving, at the one or more computer systems, a specification of a target mesh representation representing a target pose of the object in a second image frame; d) determining, with one or more processors associated with the one or more computer systems, a configuration of finite elements representing a rest state of an interior structure of the target mesh representation; e) determining, with the one or more processors associated with the one or more computer systems, a mapping function that transforms the configuration of finite elements of the rest state of the interior structure of the initial mesh representation to the configuration of finite elements of the rest state of the interior structure of the target mesh representation; and f) generating, with the one or more processors associated with the one or more computer systems, information in response to applying the mapping function to a plurality of finite elements.