![\begin{figure}\begin{center}
\subfigure[Spheres]{
{\resizebox{!}{5cm}{\includegr...
...esizebox{!}{5cm}{\includegraphics{segments/depo.eps}}}}
\end{center}\end{figure}](img13.gif) |
cells. One can easily see the regions where the spheres
overlap. Considering that for demonstration purpose only 2 of 20 spheres are
applied along the edge of the cube, the extend of redundant operations
in a regular simulation can be estimated.
The first optimization step is to limit the spheres to appropriate spherical segments as depicted in Fig. 3(b). At corners of the structures the sphere is reduced to an eighth, at edges to a one cell thick quarter circle and within planes to a one cell thick line. By these means the final geometry (Fig. 3(c)) is exactly the same as when using spheres but the number of operations is reduced drastically. With these measures the CPU time is about two orders of magnitude lower than for the complete spherical algorithm, depending on the complexity of the structure. A detailed analysis of the time requirements will follow in Section 3.1.3.
Corners, edges and planes are detected by checking the exposed sides of the surface cells. In the case of orthogonal, even facets as in Fig. 3(b) no redundant operations are introduced. The drawback of this method is, that redundancy may be reduced only to a certain extend for arbitrary curved surfaces which in the sense of surface cells are also composed by ``planes'', ``edges'', and ``corners''. Fig. 4 shows structuring elements at selected positions for isotropic deposition onto a curved surface.
[<] [^] [>] [TOC] Prev: 3.1 Isotropic Etching/Deposition Up: 3.1 Isotropic Etching/Deposition Next: 3.1.2 Linear Elements
