A method and device for generating a simplified geometric model of a real pair of spectacles. The model includes a frame, lenses, and a predefined number of surfaces and normals thereof. An orientation of these normals is taken as an exterior of a convex envelop to the real pair of spectacles. The model is obtained in a phase. A set of shots of the real pair of spectacles to be modeled is produced with different angles-of-view and using different screen backgrounds with and without the real pair of spectacles. The simplified geometric model is constructed, consisting of a predefined number of surfaces and their normal beginning with a non-dense surface mesh and using an optimization algorithm that deforms the model's mesh so that the projections of its silhouette in each of the views best match the silhouettes detected in the images.