Interactive deformable simulation of soft tissues for virtual surgery applications

Practicing surgery skills through virtual-reality based simulators is a promising methodology to improve the learning curve. Among various technical concerns, the ability to simulate deformation of soft tissues interactively and realistically is a key to the success of virtual surgery simulator. The thesis is devoted to the modeling of interactive soft-tissues deformation for virtual surgery applications. It has three major parts, including the development of the Force Propagation Model (FPM), the identification of model parameters, and the simulation of interactive cutting. The Force Propagation Model is developed to simulate the deformation of virtual objects represented by mass-spring network. It considers deformation as a process where mass points are displaced successively in an ordered manner as forces propagate via interconnecting springs. To deal with a common issue of all mass-spring based models, i.e. the specification of appropriate model parameters to simulate tissue responses, an artificial intelligence technique is employed to obtain the parameters by optimizing the Force Propagation Model against the benchmarking finite element model. Besides, the model is also extended to realize interactive cutting simulation. The significance of the thesis is that it facilitates the development of virtual surgery simulation system by providing an effective method for simulating interactive deformation of soft tissues. The work is extensible to interactive systems involving collaborative deformable simulation among multiple distributed users. In a broader view, it also has the potential for other non-medical applications such as industrial design or artistic work involving deformable soft bodies.