Growth Simulation of Digestive System Using Function Representation and Skeleton Dynamics

The embryologists found the realistic human organ models and animations of development necessary for their studies. The main idea of this paper is a methodology producing a realistic animation of development by combining the L-system growth model with a physical model. The skeleton of a digestive system is a line skeleton with a tree structure. Therefore, its growth in length can be simulated by an algebraic L-system which controls the growth of skeleton segments. The global deformations of the skeleton due to the gravity and the lack of space in abdominal cavity are simulated by a dynamics of skeleton segments. The movements that have no physical reasons such as looping are implemented by external forces applied on links controlling the organ movement in space. The convolution surfaces generated by skeletons define the final shape for growth animation. The entire system consists of two steps: First, the actual number of skeleton segments and the length of each skeleton segment is calculated from growth functions, second, the skeleton deformation in space is updated based on dynamics.