Group-Based Corotational FEM for Real-Time Large Deformation Simulation

Real-time simulation of large deformations in soft bodies has long faced a trade-off between computational efficiency and physical accuracy. This paper presents a novel Local Linear Corotated Finite Element Method that addresses this challenge through a hybrid strategy combining direct and iterative solvers. Our method decomposes the simulation domain into element groups; the dynamics within each group are resolved using a pre-computed direct method, while inter-group interactions are handled by efficient iterative constraints. This domain decomposition enables significant pre-computation, replacing runtime equation solving with fast matrix-vector multiplications. Experimental results demonstrate that the method achieves a better balance of speed and accuracy, demonstrating higher fidelity than similarly fast methods. The method supports anisotropic materials and achieves low volume change (2.95% error) under nearly incompressible conditions. Furthermore, its group-based architecture exhibits high scalability on multi-core processors, reducing computation time to 19.6 ms for a 120,000-tetrahedron model using 64 threads. These characteristics make our method well-suited for demanding applications such as surgical simulation, haptic feedback systems, and real-time digital twins, where both accuracy and performance are critical.