Real-time cutting simulation based on stiffness-warped FEM

Finite element method (FEM) is a widely used method in the simulation of virtual surgery since it can model elasticity behavior of soft tissues accurately. Linear FEM uses constant stiffness matrix that achieves fast and stable simulation but objects increase unnaturally in volume under large rotational deformation. Nonlinear FEM, on the other hand, models large deformation correctly but it is computationally complex. ldquostiffness warpingrdquo method is suitable for real-time virtual surgery applications because it updates rotational parts of the large deformations rapidly and stably. It also preserves the volume. Cutting is the main activity in virtual surgery and various methods have been presented to conduct this activity. This paper presents an improved version of the prior cutting methods used in virtual surgery. The test results indicate that the proposed surgery simulation method based on stiffness-warped FEM could perfectly be utilized in real-time virtual surgery applications.