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Action:
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Creates an elliptical pattern.
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Filename:
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kern/kern_scm/pattern_scm.cxx
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APIs:
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api_elliptical_pattern
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Syntax:
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(pattern:elliptical center normal num
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[not-rotate=#f root [angle=360
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[ratio=1 major-axis]]])
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Arg Types:
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center
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position
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normal
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gvector
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num
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integer
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not-rotate
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boolean
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root
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position
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angle
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real
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ratio
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real
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major-axis
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gvector
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Returns:
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pattern
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Description:
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Creates a one-dimensional elliptical pattern defined by an axis of rotation.
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center and
normal define the (global) position and orientation of the axis.
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num argument defines the number of entities in the pattern.
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When
not-rotate is
#t, the elements of the pattern are kept in a fixed, relative orientation. In which case,
root is required because it defines the position mapped to the pattern sites.
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angle defines the angular extent of the pattern, with positive/negative values producing patterns proceeding clockwise/counter-clockwise (accordingly) about the normal vector.
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ratio defines the ratio of minor/major radii of the pattern.
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major-axis defines the direction of the ellipse's major axis.
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Example:
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; pattern:elliptical
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; Make a prism to demonstrate command.
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(define height 1)
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;; height
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(define maj_rad 1)
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;; maj_rad
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(define min_rad 0.5)
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;; min_rad
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(define num_sides 3)
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;; num_sides
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(define prism (solid:prism height maj_rad
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min_rad num_sides))
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;; prism
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; Output Original
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; Redefine position of origin.
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(define origin (position 1 2 3))
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;; origin
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; Reposition prism.
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(define transform (entity:transform prism
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(transform:axes origin (gvector 1 0 0)
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(gvector 0 1 0))))
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;; transform
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; Make a pattern.
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(define center (position 11 2 3))
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;; center
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(define normal (gvector 0 0 1))
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;; normal
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(define num 24)
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;; num
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(define not-rotate #f)
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;; not-rotate
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(define root origin)
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;; root
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(define ang 360)
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;; ang
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(define ratio 0.5)
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;; ratio
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(define major-axis (gvector 2 1 0))
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;; major-axis
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(define pat (pattern:elliptical center normal num
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not-rotate root ang ratio major-axis))
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;; pat
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; Apply the pattern to the prism.
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(define body (entity:pattern prism pat))
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;; body
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; Output Result
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Figure 14-3. pattern:elliptical
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