In a process for generating garment model data representative of a piece of garment, input image data containing a view of the piece of garment are processed. A type of wearing condition is determined as at least one of a first type of worn garment and of a second type of not-worn garment. If the first type is determined, a shape of the piece of garment and a shape of the person wearing the garment are identified utilizing an active contour modelling approach based on a preset body model. The identified shapes are adapted based on a garment template model. The garment model data are determined from the input image data based on the adapted identified shapes. If the second type is determined, a shape of the piece of garment is identified. The input image data are iteratively compared with a respective garment template model to identify at least one matching garment template model. The identified shape is aligned with a shape of the at least one matching garment template model and the garment model data are determined from the input image data based on the identified shape and on results of the aligning.