The ultimate goal of the application described in this paper is the conversion of two-dimensional sketches into three-dimensional CAD curves and surfaces. The first creative step of planning and outlining a conceptual idea often is realised in so-called scribbles (conceptual sketches). Normally, they are scribbled with pencils on sheets and thus only can be used for background information to develop the virtual three- dimensional shape. A new method enables the conceptual designer to scan paper scribbles and afterwards convert them into a virtual sketch model. The virtual sketch model includes all the "fuzziness" of the scribble and the therein expressed conceptual steps but is automatically represented in a sequence of real B-Spline curves. The conceptual designer can develop it into the final concept and into the three- dimensional CAD elements.
