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Action:
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Gets the tangent at the start of 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:start-tan edge-or-curve)
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Arg Types:
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edge-or-curve
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curve | edge
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Returns:
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gvector
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Errors:
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EDGE with no
CURVE
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Description:
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Returns the tangent at the start of an edge or curve.
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edge-or-curve specifies an edge or a curve.
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Example:
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; curve:start-tan
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; Create circular edge 1.
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(define edge1
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(edge:circular
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(position 0 0 0) 15 0 145))
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;; edge1
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; Determine circular edge 1's start tangent vector.
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(curve:start-tan edge1)
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;; #[gvector 0 1 0]
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; Create circular edge 2.
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(define edge2
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(edge:circular
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(position -5 -10 10) 35 25 245))
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;; edge2
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; Determine circular edge 2's start tangent vector.
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(curve:start-tan edge2)
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;; #[gvector -0.422618261740699 0.90630778703665 0]
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