Animation interactive et modélisation par le dessin : applications pédagogiques en médecine (Interactive Animation and Modeling by Drawing - Pedagogical Applications in Medicine)

Medicine is a discipline where visualization is an essential component of learning. However, the three-dimensional, dynamic structure of the human body poses difficult teaching challenges. There is a need for truly interactive computer tools that will enable students to create and manipulate computer models, not just watch them. We propose different approaches with that goal in mind. We were first interested in interactive physically-based animation of anisotropic elastic materials. One possible application scenario is an anatomy course on heart physiology where students can build interactive samples of cardiac muscular tissue. To achieve this, our model exhibits two key features. The first one is a low computational cost that results in high frame rates; the second one is an intuitive \emph{system image} that ensures easy control by the user. Next, we were interested in interaction in three dimensions using two-dimensional input, either for annotating existing models, or for creating new models; taking advantage of the fact that drawing practice is still considered a fundamental learning method by some anatomy teachers in the French medical school curriculum. Our 3D drawing system has a stroke representation that enables drawing redisplay when the viewpoint changes. Moreover, this representation can be mixed freely with existing polygonal surfaces for annotation purposes. In contrast, our modeling by drawing tool uses information from both stroke geometry and the drawn image, to allow three-dimensional modeling without explicit depth specification.