The DIERS formetric is a light-optical scanning method based on Video-Raster-Stereography (VRS). Accordingly, the system consists of a light projector which projects a line grid on the back of the patient which is recorded by an imaging unit. A computer software analyzes the line curvature and generates from it  – by means of the method of the Photogrammetrie – a three-dimensional model of the surface, comparable to a plaster cast.