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Surface Discretization

The surface discretization is based on templates fitted into quadrants of quad tree built on the surface or extracted from the octal tree of the region bounded by the surface. The number of templates is considerably reduced by the fact that only one node is allowed to be on side of a quadrant. This is a direct consequence of ``1:2 rule'' applied during the parametric tree construction. The basic set of templates currently used is displayed in Figure 12. Although there are known templates yielding all-quadrilateral meshes, these have not been used because of incompatibility with consequent region discretization for which the all-hexahedral templates are not available. This is the reason why triangular elements, treated as degenerated quadrilateral elements, are accepted. After all quadrants have been filled in with appropriate template the final surface mesh is smoothed. The same technique as used in the sequential mesh generator is used optionally extended by preserving symmetry (if any) at somewhat higher computational cost. However, the quality of the optimized mesh is a little bit deteriorated by the irregularity of the mesh connectivity due to the common presence of triangular and quadrilateral elements. Also the distribution of boundary nodes arising from the less flexible curve smoothing has a negative influence on the overall surface mesh quality.



Next: Region Discretization Up: Mesh Generation Previous: Curve Discretization

Daniel Rypl
2005-12-03