CREATION OF A LINEAR OR PLANAR SHAPE

A watermark is embossed into a model of a linear or surface shape, especially a non-uniform rational B-splines model. The model has a plurality of splines, the combination of which forms the shape. Control points are assigned to the splines such that a course of the respectively associated spline can be modified and thus be controlled by changing the position of the control points and/or weights of the control points. Nodes which are located in a section of the shape that is formed by the respectively associated spline are allocated to the splines. In order to change the shape (the modified curve runs through point Cmod) when a watermark is embossed into the model, the position of at least one control point is modified, the weight by which a control point affects the shape and thus influences at least one area of the shape is modified, and/or an additional control point is inserted into the model. At least one additional node is inserted into the model (new node at u=1.1875 on the modified curve) in order to obtain information on how the change of the shape can be reversed.