Simulation of deformable solids in interactive virtual reality applications

Simulation of deformable objects has become indispensable in many virtual reality applications. Linear finite element algorithms are frequently applied in interactive physics simulation in order to ensure computational efficiency. However, there exists a variety of situations in which higher order simulation accuracy is expected to improve physical behaviors of deformable objects to match their real-world counterparts. For example in the context of virtual surgery, interactive surgical manipulations mandate algorithmic requirements to maintain both interactive frame rates and simulation accuracy, presenting major challenges in simulation methods. In this paper, we present an interactive system for efficient finite element based simulation of hyperplastic solids with more accurate physics behaviors compared with that of standard corotational methods. Our approach begins with a physics model to mitigate drawbacks of the corotational linear elasticity in preserving energy and momenta. A new damping model is presented which takes into account the differential of rotation to compensate the loss of momenta due to rotations. Thus, more accurate simulations can be achieved with this new model, whereas standard corotational methods using rotated damping to handle energy dissipation does not preserve momenta. We then present a real time simulation framework for computing finite element based deformable solids with full capability allowing complex objects to collide and interact with each other. A constrained system is also provided for robust control and the ease of use the simulation system. We demonstrate the parallel implementation to enable realistic and stable physics behaviors of large deformations capable of handling unpredictable user inputs in interactive virtual environments. The implementation details and insights on practical considerations in implementation such as our experience in parallel computation of the physics for mesh-based finite element objects would be useful for people who wish to develop real-time applications in this area.