Abstract: Physically-based soft bodies are difficult to animate for anisotropic and heterogeneous materials. Explicitly modeling a desired material behavior by tuning the constitutive parameters is a difficult, tedious and sometimes impractical task for an animator. Even with linear constitutive materials, there are still dozens of independent parameters to tune. In this paper, we propose a new technique to ease the animators' effort when modeling complex material behaviors. Our key idea is to treat the original complex material as the composite of a matrix and structure elements. These two constituent materials are both easy to simulate because the matrix is homogeneous and isotropic, while the structure elements have simple and intuitive deformation mode. In this way, complexity in tuning parameters is greatly reduced. By proper embedding structure elements into the matrix, an animator can design diverse and creative material behavior without tedious parameter tuning work. Our results illustrate that our approach is intuitive, easy-to-use and has potential for further extensions for physically-driven solid animation.