Abstract: This paper selected human soft tissue model as a research object and proposed local mass-spring/damper(ALMSDM)according to characteristics of medical palpation training．Dynamic characteristics of this model include position-changing and extensible area,which improves the restrictions of static limitation in local modeling method in existing literature and resolves the problem of poor recovering ability and large volume data in global surface model．And the strategy of local updating for vertex normal and pre-computing was also proposed combining ALMSDM’s features．This strategy dramatically enhances the real-time of system whose performance is assessed from recovery,feedback force and real-time under different models．This can guarantee the accuracy and real-time of virtual soft tissue deformation and simulation,thus verifies feasibility and universal property of this proposed algorithm.

Key words: Virtual surgery,Soft tissue deformation,Local dynamic model,Tactile feedback,Surface model,Body model