To create a new shape, the user sketches its silhouette. From the sketched curve, our system generates a surface composed of smoothly joined generalized cylinders, a skeleton, and skin weights attaching the surface to the skeleton. First, the user’s sketched curve is closed and treated as a planar polygon (Fig. 2 (a)). The polygon is decomposed into cylindrical regions with well defined local symmetry, and connecting regions lacking such symmetry (Section 2.1). The surface and the skeleton are then each generated (Sections 2.2 and 2.3), and, as a final step, the surface is attached to the skeleton by automatically computing skin weights (Section 2.4).These steps are all computed instantaneously as soon as the user completes the stroke by releasing the mouse button.