little_helpers/tikz/sketch-0.2.161/Doc/sketch/Polyline-sweeps.html

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  56 <h4 class="subsection">2.7.2 Polyline sweeps</h4>
  57
  58 <p>Sweeping a polyline produces a
  59 <a name="index-line-sweep-105"></a><a name="index-swept-line-106"></a><a name="index-surface-107"></a>surface composed of many faces.
  60 <a name="index-faces-108"></a>The unbroken helix in the
  61 example <a href="Helix-with-cull-set-false-then-true.html#Helix-with-cull-set-false-then-true">Helix with cull set false then true</a> is produced by this
  62 code (plus a surrounding <tt>put</tt> rotation to make an interesting
  63 view; this has been omitted).
  64 <a name="index-def-109"></a><a name="index-sweep-110"></a><a name="index-rotate-111"></a><a name="index-translate-112"></a><a name="index-cull-113"></a><a name="index-linewidth-114"></a>
  65 <pre class="verbatim">
  66   def K [0,0,1]
  67   sweep[cull=false] {
  68     60,
  69     rotate(10, (0,0,0), [K]) then translate(1/6 * [K])
  70   } line[linewidth=2pt](-1,0)(1,0)
  71 </pre>
  72 Again, 60 segments of the helix
  73 <a name="index-helix-115"></a>are produced by connecting 61
  74 instances of the swept line.  Options
  75 <a name="index-options_002c-sweep-116"></a>applied to the sweep, here
  76 <tt>cull=false</tt>, are treated as options for the generated polygon
  77 or polyline.  Options of the swept line itself, here
  78 <tt>linewidth=2pt</tt>, are ignored, though with a warning. This
  79 <tt>def</tt> is a <dfn>vector</dfn> definition,
  80 <a name="index-definition_002c-vector-117"></a><a name="index-vector-definition-118"></a>which must be referenced
  81 with square brackets, e.g. <tt>[foo]</tt>.
  82 <a name="index-reference_002c-vector-119"></a><a name="index-_005bfoo_005d_0040r_007b_002c-vector-reference_007d-120"></a>
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