| The traditional volume model generation method is prone to create broken surface when using non-manifold surface mesh model.This thesis presents an efficient and robust method for constructing deformable volume model.The proposed method can process arbitrary triangular geometry including unorientable and non-manifold triangle soups.The volume model consist of hexahedral voxels and links,which can be used for interactive cutting and deformation simulation.The feasibility and robustness had been verified through interactive cutting test which using octree based cutting method.The specific research work has the following aspects:(1)Beacuase the actual volume bounded by the non-manifold surface are undefined in mathematics,a preprocessing process is designed to generate manifold surface for a pseudo volume.The pseudo volume are bounded by a manifold and closed surface which are generated using distance field technique and isosurface extraction method with topological guarantees(Manifold Marching Cubes or Manifold Dual Contouring).(2)The calculation of distance field and isosurface extraction method are generally time-consuming operation.This thesis present a number of highly effective improvements of previous work to allow faster GPU-accelerated distance field calculation for arbitrary triangular geometry by combining the both advantages from GPU rasterization and OpenCL parallel programming framework.Compared with traditional characteristic scan conversion method which based on Voronoi diagram conception,the proposed distance field algorithm can be applied to arbitrary triangular geometry.Compared with the multi-threaded distance field computation method using spatial partition,the efficiency of the algorithm can be improved by 10-12 times.(3)The whole process of manifold surface generation get further improved by using GPU to accelerate the isosurface extraction method.It also lead a less memory consumption.(4)After the preprocessing process,there are a series of algorithm to constuct deformable volume data structure as voxelization,surface reconstruction and the generation of the octree grid,performing on the closed manifold surface.The voxelization algorithm in this thesis also can be directly applied to some non-manifold surfaces with slight cracks and tiny holes,thus eliminating the need for pre-processing for such models. |
