Hans Hagen is a professor of computer science at the University of Kaiserslautern. One of his major research contributions were geometric modeling techniques called "Variational Design" of curves and surfaces. His curve and surface interrogation methods are among his many contributions to topological and geometric aspects of scientific visualization. Hans Hagen has published over four hundred articles in journals, books and conference proceedings. His research interests are deep and very broad. His work concentrates on physically based modeling, curve and surface interrogation and topology-based visualization. Particular emphasis is placed on variational design. The key idea is include energy minimization as an integral part of the algorithm and the underlying mathematics. This concept is now industry standard. Hans Hagen has a strong background in differential geometry and topology. His geometric modeling publication record started with a work on geometric splines, where he introduced a torsion continuous spline curve. Thereafter he developed together with Guido Brunnett and Paolo Santarelli the Variational Design methodology and a solution to the twist input and compatibility twist problem of the Coons patches. Triangular patches did not have "curvature modeling facilities" for many years. Hans Hagen had a strong impact on the Geometric Modeling community. He started the world-class Dagstuhl Seminar Series on Geometric Modeling that regularly brings together the leading experts of the field in a relaxed unmatched format that stimulated a lot of ideas. He served as associated editor for major journals like CAD and CAGD for many years. In addition, he served on numerous program committees. Regarding scientific visualization, he had a great impact too. From 1999 to 2003 he was the editor in chief of IEEE Transactions on Visualization and Computer Graphics. He serves for many years as International Liaison Officer of the Visualization and Graphics Technical Committee. Currently, he is on the Steering Committees of IEEE SciVis and EuroVis, the two leading conferences in Scientific Visualization. He was also the Chair of the TopoInVis Steering Committee which organizers the biannual TopoInVis Workshops to promote topological methods in visualization. He got the for his achievements in Geometric Modeling in 2002. His lifetime contributions to Scientific Visualization were honored by the .
