1. A computer implemented method of obtaining data for determining a three-dimensional shape of a medical device, the method comprising: rendering a computer-generated three-dimensional representation of a target tissue from computer readable image data of the target tissue wherein the target tissue comprises two portions, a portion with a defect and a portion without a defect; identifying anatomical landmarks on the computer-generated three-dimensional representation of the target tissue; superimposing onto the rendered computer-generated three-dimensional representation of the target tissue a three-dimensional template to span the defective portion; deforming the three-dimensional template to match the identified anatomical landmarks to determine the three-dimensional shape of the medical device.