Research On The Soft Tissue Deformation Based On Physical Properties And Geometrical Characteristics

In recent years, grid deformation technology is one of research hotspots in computer graphics and is used in many fields such as animation, film and television ads, computing visualization and so on. In medical simulation and auxiliary treatment system, soft tissue deformation is an important application of grid deformation technology.Currently, two types of grid deformation algorithms are widely used. They are the method based on geometric feature and the method based on physical models. This paper focuses on two kinds of method, one is differential deformation, and the other is based on mass-spring model. As for the first method, this paper introduces the calculation formula of Laplacian differential coordinate and the weights such as Unit weight, Cotangent weight and Tangent weight are also introduced. The deformation technology of using differential coordinates for deformation is elaborated and is implemented. The experiment shows that this method.This method is used to gum deformation in virtual orthodontics system. Experiments show that this approach is fast but deformation effect is not good when the grid is complex. For the method based on mass-spring model, model establishment and its deformation steps are introduced. It is also used to the gum deformation. Experiments show that this method performs well but consumes very long time.This paper proposes a new method that combines the above methods for rapid soft tissue deformation. The method based on mass-spring model gives biomechanical properties to the geometric model, but its deformation in time consumption is long. The method based on Laplacian differential coordinates possesses the advantages of keeping data detail information. There are four steps to implement the algorithm. First, simplifies the original mesh with its boundary kept; then the method based on mass-spring model is adapted for integral deformation; third, the method based on Laplacian differential coordinates is used for local deformation; final, the local information is add to the integral deformation. This method speeds up the soft tissue deformation, preserves enough original details and simulates the soft tissue deformation well.The algorithms in this paper are based on the Windows XP operating system and Visual Studio 2010, and C++ language combined with VTK and OpenCV library are used for implementation. The new method is applied to the automatic row of teeth software system. Practice shows that this method is effective and feasible.