A new modeling approach by global and local characterization

In this paper, we introduce a new approach for modeling closed surfaces. After working with several methods, we think that none really takes into account both the local and global characteristics of an object within a single coherent model. For instance, parametric surfaces endure changes of topology with difficulty and can mainly be used for local modifications of an object’s surface. On the opposite, implicit surfaces allow a good global characterization of an object, thanks to a skeleton. However, the latter quickly shows its limits when it comes to small variations on an object’s surface. After exposing several limits of classical existing approaches, we present the concept of a double characterization of an object, using two skeletons (intern and extern) and transition layers that link these two entities. The intern and extern skeletons define the object’s topology, morphology and geometry in a different way than with the usual definition of a skeleton. In the end of this paper, we use this modeling approach in a reconstruction context.