1. A method for manufacturing a hearing device, the method comprising the steps of: reconstructing a three-dimensional shape of a surface of at least a portion of at least one of an ear canal or a concha, the reconstructing comprising the steps of: using a chromatic coded distance measurement technique for determining a multitude of distance values respectively representative of a distance to each point of a multitude of points on said surface, using the chromatic coded distance measurement technique further comprising the steps of: (a) illuminating said multitude of points by means of polychromatic light emitted from a probe located near or in said at least one of said ear canal or concha; (b) collecting light reemitted from said surface upon said illumination, (c) analyzing said collected light with respect to color of said light, and (d) obtaining said multitude of distance values from said analysis; tracking at least one of: a position in space or an orientation in space of said probe; a position in space or an orientation in space of said at least one of said ear canal or concha; or a relative position or mutual orientation of said probe and said at least one of said ear canal or concha; and generating corresponding tracking data and reconstructing said three-dimensional shape based on said multitude of distance values and said tracking data; and manufacturing at least a part of said hearing device, based on said reconstruction.