1. A computer-assisted method of using volumetric image data to construct a representation of a virtual organ, the method comprising: determining, using one or more computers, a set of one or more candidate segments in the volumetric image data; identifying, using the one or more computer, a set of one or more landmark segments from the set of candidate segments; computing, using the one or more computer, a characteristic path for each segment in the set of candidate segments; and creating, using the one or more computer, a first combined path by connecting the characteristic paths, wherein the connecting is performed using a cost network; orienting, using the one or more computer, the characteristic paths for the one or more candidate segments to be consistent with a start point and an end point, wherein the candidate segment is a cecum segment, and wherein orienting the associated characteristic path comprises: if the cecum segment spans a sufficient sagittal distance, then orienting the path such that an endpoint with a maximum x value precedes an endpoint with a minimum x value; if the cecum segment spans a sufficient axial distance, then orienting the path such that an endpoint with a maximum z value is the start of the path; if the cecum segment does not span a sufficient sagittal distance or a sufficient axial distance, then orienting the path by: projecting the path onto a sagittal plane to create a sagittal projection; and orienting the path such that it represents a clockwise path in the sagittal projection.