Fabrication of freeform objects by principal strips

Abstract

Current CAD modeling techniques enable the design of objects with aesthetically pleasing smooth freeform surfaces. However, the fabrication of these freeform shapes remains challenging. Our novel method uses orthogonal principal strips to fabricate objects whose boundary consists of freeform surfaces. This approach not only lends an artistic touch to the appearance of objects, but also provides directions for reinforcement, as the surface is mostly bent along the lines of curvature. Moreover, it is unnecessary to adjust the bending of these orthogonal strips during the construction process, which automatically reforms the design shape as if it is memorized, provided the strips possess bending rigidity. Our method relies on semi-isometric mapping, which preserves the length of boundary curves, and approximates angles between boundary curves under local minimization. Applications include the fabrication of paper and sheet metal craft, and architectural models using plastic plates. We applied our technique to several freeform objects to demonstrate the effectiveness of our algorithms.