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The grid aspect ratio is the ratio of the
u and
v lengths of a
uv grid cell. Thus, the aspect ratio is used only when the grid mode is something other than
AF_GRID_NONE. The
u and
v lengths are in object space. The algorithm tries to make the aspect ratio equal to the one specified, but this is not guaranteed.
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The grid aspect ratio is defined as the ratio of the geometric length of a grid in the
u parameter direction to the geometric length of the grid in the
v parameter direction. The faceter attempts to make grids having a ratio specified by the
grid_aspect_ratio refinement parameter. For instance, setting the aspect ratio to 1.0 indicates that the grid should be as square as possible. The algorithm which tries to create grids having a specified aspect ratio has been modified to give better grids when the aspect ratio is 1.0.
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The
set_grid_aspect_ratio method from the
REFINEMENT class specifies the approximate aspect ratio of each cell in the grid. If the value is close to 1, then the cell is close to a square. This does not guarantee the aspect ratio of the facet, which may consist of only a part of a cell.
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Figure 1-4 illustrates two cases of grid aspect ratio. The refinement values are specified in Table 1-3.
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Figure 1-4. Grid Aspect Ratio
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Table 1-3. Grid Aspect Ratio
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