Next: Quadrilateral Generation Up: Generation of Quad-dominant Meshes Previous: Generation of Quad-dominant Meshes


Mixed Mesh Generation

The basic idea of producing a quadrilateral is based on generating consecutively two adjacent triangles that can be merged to form a valid quadrilateral element. The triangles are created using the triangular kernel detailly described in Subsection Surface Triangulation of Section Direct Triangulation of 3D Surfaces. In order to make the shape of the generated quadrilateral elements close to a square, which is considered to be optimal for uniform meshes, the triangular kernel has to be subjected to minor modifications that can be identified as:

Since it is not guaranteed that the boundary of the surface (domain) is discretized into an even number of edges, an isolated triangle may remain in the mesh. Moreover, in the presented algorithm, the formation of a quadrilateral is relaxed whenever it is too difficult or impossible to generate immediately the second triangle that could be merged with the first one into a valid quadrilateral (typically in the mesh transition zones and front closure zones). The resulting mesh is therefore of mixed nature containing potentially a large percentage of triangular elements.



Next: Quadrilateral Generation Up: Generation of Quad-dominant Meshes Previous: Generation of Quad-dominant Meshes

Daniel Rypl
2005-12-07