A data compression method for tetrahedral meshes

In this paper, a loose-less compression scheme is presented for Finite Element Analysis (FEA) data. In this algorithm, all FEA cells are assumed to be tetrahedra. Therefore a cell has at most four neighboring-cells. Our algorithm starts with computing the indices of the four adjacent cells for each cell. The adjacency graph of the data set is formed by representing a cell by a vertex and by drawing an edge between two cells if they are adjacent. Then the adjacency graph is traversed by using a depth first search, and the mesh is split into tetrahedral strips. In a tetrahedral strip, every consecutive cells share a face, and thus only, one vertex index has to be specified for defining a tetrahedron. Therefore. the memory, space required for storing the mesh is reduced. The tetrahedral strips are encoded by using four types of instructions and converted into a sequence of bytes. Unlike most 3D geometrical compression algorithms, the indices of vertices are not changed in our scheme. Rearrangement of vertex data is not required.