A Novel Method for Boundary Condition Computation in Soft Tissue Deformation

Simulating the soft tissue deformation based on bone-related planning is one of the most difficult issues in generating realistic motion of soft tissues. The difficulty of this problem arises from unclear boundary conditions. In facial soft tissue deformation, the boundary conditions of the finite element modeling are related to the bone movements. In order to better map the bone movements to the soft tissue model, a fast and robust computational strategy for boundary conditions is presented in this paper. First, a collision detection algorithm is employed to query contact position after repositioning of bones. Then, an improved 3D discrete distance field algorithm is proposed to perform imposed displacement computation of contact vertices. Finally, boundary conditions are calculated in terms of the imposed displacements. This approach can automatically handle boundary conditions of the complex geometrical modeling without prior assumption or knowledge about the position of contacts. The effectiveness of our method is demonstrated on complex soft tissue deformation.