Incorporating Fiber Controls into FEM Model for Transversely Isotropic Materials

Abstract

Physically plausible deformable models based on continuum mechanics have been a hot topic in computer graphics for decades, and many models have been proposed to improve performance speed and stability. However, most of the existing models focus on isotropic materials, while elastic objects with complex anisotropic properties are less studied. Based on the observation that a large group of objects have specific internal structures (fibers) that determine their anisotropic behavior, we propose a fiber incorporated corotational FEM model that can approximate longitudinally anisotropic deformation. First, a fiber orientation field is used to establish local frames for each element; then, the orientation information is combined into the FEM model by adding local transformations on element stiffness matrices. This proposed model can provide a control for directable deformations, and yields realistic anisotropic deformations. Large deformations can be accommodated; meanwhile, with pre-computation it adds no computational cost to the existing corotational FEM model during simulation. Convincing experimental results and analytical comparisons are presented, together with an accompanying video demonstration.