Abstract: We present a method for progressive deforming meshes. Most existing mesh decimation methods focus on static meshes. However, there are more and more animation data today, and it is important to address the problem of simplifying deforming meshes. Our method is based on deformation oriented decimation (DOD) error metric and dynamic connectivity updating (DCU) algorithm. Deformation oriented decimation extends the deformation sensitivity decimation (DSD) error metric by augmenting an additional term to model the distortion introduced by deformation. This new metric preserves not only geometric features but also areas with large deformation. Using this metric, a static reference connectivity is extracted for the whole animation. Dynamic connectivity updating algorithm utilizes vertex trees to further reduce geometric distortion by allowing the connectivity to change. Tem- poral coherence in the dynamic connectivity between frames is achieved by penalizing large deviations from the reference connectivity. The combination of DOD and DCU demonstrates better simplification and triangulation performance than previous methods for deforming mesh simplification.