Research On Soft Tissue Deformation And Cutting Based On Local Volume Grid In Virtual Surgery Simulation

Virtual surgery is an important application of virtual reality technology in the field of modern medicine.It has the advantages of saving the cost of training doctors and improving the success rate of surgery.Soft tissue deformation and cutting are two key technologies of virtual surgery.How to balance the real-time and authenticity of the system is the key of soft tissue deformation and cutting simulation.In order to solve this problem,this paper studies the modeling method and cutting algorithm of soft tissue deformation.First of all,soft tissue simulation is the key for virtual surgery.This is because the visual and force feedback modules in virtual surgery simulation rely on the computational data provided by the soft tissue model.These data are the guarantee for the immersion and training effect of the virtual surgery simulation system.The surface mesh constructed by the traditional method has no internal structure and can not simulate the internal characteristics of the soft tissue.The volume mesh constructed by the commonly used volumetric meshing method has a large increase in the amount of calculation of newly added particles,which seriously affects the real-time performance of the system.Therefore,a particle spring model based on local volume mesh is proposed.The local volume mesh is generated by the spatial segmentation algorithm and consists of two parts: one part simulates the surface mesh of the topological structure of the soft tissue,and the other part is the internal structure of the simulation model obtained by the location of the surface mesh in space.An internal grid of discrete points.The experimental results show that the real-time performance of the particle spring model based on the local volume mesh is similar to that of the mass-spring model based on the surface mesh;the deformation effect of the mass structure spring model constructed by the traditional partition method is similar,but the real-time performance of the model Better performance.Second,the traditional surface mesh particle spring model has poor deformation and recovery.In order to make the local body mesh have good recoverability when large deformation occurs,a bending spring is introduced to physically model the local body mesh.The bending spring is sandwiched between the initial vector and the real-time vector of the two adjacent mass points of the model.The angle calculates the spring force to achieve the ability of the spring to resist bending.Experimental results show that compared with the traditional surface mesh particle spring model,the model has very good deformation and restoration effects.Finally,cutting is a common operation in virtual surgery.The traditional mesh cutting algorithm has the problem that the topological structure of the mesh model is complex and the cutting algorithm is difficult to implement.Therefore,a time-division cutting algorithm is proposed.The algorithm divides the entire cutting process into three periods for processing.The algorithm divides the cutting process into three stages: initial cutting,path cutting,and ending cutting.The algorithm classifies the types of intersections between the virtual surgical instruments and the mesh grid boundary of the mesh model,and reconstructs the topological structure of the cut triangular patches according to the type of intersection.The experimental results show that the algorithm can realistically simulate the incision effect.Compared with the traditional cutting algorithm,the algorithm is relatively simple and the topological structure of the model can be reconstructed regularly.It is a relatively comprehensive new cutting algorithm.