Smooth curves and surfaces can be characterized as minimizers of squared curvature bending energies subject to constraints. In the univariate case with an isometry (length) constraint this leads to classic non-linear splines. For surfaces, isometry is too rigid a constraint and instead one asks for minimizers of the Willmore (squared mean curvature) energy subject to a conformality constraint. We present an efficient algorithm for (conformally) constrained Willmore surfaces using triangle meshes of arbitrary topology with or without boundary. Our conformal class constraint is based on the discrete notion of conformal equivalence of triangle meshes. The resulting non-linear constrained optimization problem can be solved efficiently using the competitive gradient descent method together with appropriate Sobolev metrics. The surfaces can be represented either through point positions or differential coordinates. The latter enable the realization of abstract metric surfaces without an initial immersion. A versatile toolkit for extrinsic conformal geometry processing, suitable for the construction and manipulation of smooth surfaces, results through the inclusion of additional point, area, and volume constraints.
Christoph Bohle, Paul Peters, and Ulrich Pinkall.
Constrained Willmore surfaces.
Calc. Var. Partial Differential Equations, 2008.
Dr. Albert Chern +
Prof. Dr. Olga Diamanti +
University: TU Graz, Department of Mathematics, NT04012
Address: Kopernikusgasse 24/IV, 8010 Graz, AUSTRIA
Tel: +43 316 8738442
Dr. Felix Knöppel +
Prof. Dr. Ulrich Pinkall +
University: TU Berlin, Institut für Mathematik, MA 822
Address: Straße des 17. Juni 136, 10623 Berlin, GERMANY
Tel: +49 30 31424607