A method for generating a three-dimensional model of a head including at least a portion of a face, comprising: obtaining a distance image of the head using a distance-measuring device having an imaging position, the distance image comprising for each of a two- dimensional array of distance pixels, a respective distance value indicating a distance from the measuring position to a corresponding point in a field of view of the distance-measuring device, the distance image including a face portion corresponding to the at least a portion of a face; estimating the position, relative to the imaging position, of a longitudinal axis of the model of the head based on the at least one dimension; based on the longitudinal axis, generating the three dimensional model of the head based on the position of the longitudinal axis.