Developer: RhinoScript
Summary: Demonstrates how to chop up a curve into segments and spaces.

Is there a way to divide a curve into a dashed line (defining segment and spacing length)?

See the following script.

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' DivideCurveDashed.rvb -- October 2010
' If this code works, it was written by Dale Fugier.
' If not, I don't know who wrote it.
' Works with Rhino 4.0 and 5.0.
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Option Explicit 
 
' Divides a curve into "dashed" segments
Sub DivideCurveDashed
 
  Dim curve, slength, dlength
  Dim i, length, pt, t, dom, results
 
  curve = Rhino.GetObject("Select curve to divide", 4, True)
  If IsNull(curve) Then Exit Sub
 
  slength = Rhino.GetReal("Segment length", 1.0)
  If IsNull(slength) Then Exit Sub
  If (slength <= 0) Then Exit Sub  
 
  dlength = Rhino.GetReal("Dash length", 1.0)
  If IsNull(dlength) Then Exit Sub
  If (dlength <= 0) Then Exit Sub
 
  Call Rhino.EnableRedraw(False)
  i = 0
 
  Do
 
    If (i Mod 2 = 0) Then
      length = slength
    Else
      length = dlength
    End If
 
    pt = Rhino.CurveArcLengthPoint(curve, length)
    If IsNull(pt) Then Exit Do
 
    t = Rhino.CurveClosestPoint(curve, pt)
 
    If (i Mod 2 = 0) Then
      results = Rhino.SplitCurve(curve, t, True)
      curve = results(1)
    Else
      dom = Rhino.CurveDomain(curve)
      curve = Rhino.TrimCurve(curve, Array(t, dom(1)), True)
    End If
 
    i = i + 1
 
  Loop While True    
 
  Call Rhino.EnableRedraw(True)
 
End Sub
 
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' Drag & drop and alias creation stuff
Rhino.AddStartUpScript Rhino.LastLoadedScriptFile
Rhino.AddAlias "DivideCurveDashed", "_-RunScript (DivideCurveDashed)"