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Action:
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Gets the normal projection of a position onto an edge or curve.
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Filename:
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kern/kern_scm/crv_scm.cxx
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Syntax:
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(curve:project-pos edge-or-curve in-pos [parameter=0])
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Arg Types:
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edge-or-curve
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curve | edge
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in-pos
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position
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parameter
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real
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Returns:
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pair (position . real)
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Errors:
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EDGE with no
CURVE
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Description:
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This extension returns a pair (position .
real). The first term
position is the orthogonal projection of the input
test-position onto the input
curve curve. The second term
real is the corresponding parameter value in the range 0 to 1.
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edge-or-curve specifies an edge or a curve.
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in-pos specifies the location to compute the parameter on the curve.
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parameter is an optional argument specifying the location on the curve to compute from the
in-pos. If
parameter is not specified, the closest parameter is computed from the start of the curve. If
parameter is specified, the parameter is computed from the input
in-pos value and is always applied in the positive parameter direction.
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Example:
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; curve:project-pos
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; Create a circular edge.
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(define edge1
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(edge:circular
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(position 0 0 0) 25 0 185))
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;; edge1
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; Compute the normal projection of two positions
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; onto the edge.
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(curve:project-pos edge1 (position 0 0 0) 0.63)
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;; (#[position -11.174465516778 22.3636159959506 0]
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;; . 0.63)
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(curve:project-pos edge1 (position 25 25 25))
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;; (#[position 17.6776695296637 17.6776695296637 0]
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;; . 0.243243243243243)
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