Real-time simulation of contact and cutting of heterogeneous soft-tissues

International audienceThis paper presents a numerical method for interactive (real-time) simulations, which considerably improves the accuracyof the response of heterogeneous soft-tissue models undergoing contact, cutting and other topological changes. We providean integrated methodology able to deal both with the ill-conditioning issues associated with material heterogeneities,contact boundary conditions which are one of the main sources of inaccuracies, and cutting which is one of the mostchallenging issues in interactive simulations. Our approach is based on an implicit time integration of a non-linear finiteelement model. To enable real-time computations, we propose a new preconditioning technique, based on an asynchronousupdate at low frequency. The preconditioner is not only used to improve the computation of the deformation of thetissues, but also to simulate the contact response of homogeneous and heterogeneous bodies with the same accuracy. Wealso address the problem of cutting the heterogeneous structures and propose a method to update the preconditioneraccording to the topological modifications. Finally, we apply our approach to three challenging demonstrators: i) asimulation of cataract surgery ii) a simulation of laparoscopic hepatectomy iii) a brain tumor surgery