Version: 4.0
Summary: How to set the length of a curve object.

The following example RhinoScript subroutine demonstrates how to set the overall length of a selected curve object. The subroutine prompts the user to pick a curve and to enter a new overall length. From this, the script determines which end of the curve to modify and trims it accordingly.

 Option Explicit
 
 Sub SetCrvLength
 
   Dim crv, lold, lnew, dom, pts, t
 
   crv = Rhino.GetCurveObject("Select curve to set length", 4, True)
   If Not IsArray(crv) Then Exit Sub
 
   If Rhino.IsCurveClosed(crv(0)) Then
     Rhino.Print "Cannot set the length of closed curves."
     Exit Sub
   End If
 
   lold = Rhino.CurveLength(crv(0))
   lnew = Rhino.GetReal("New curve length", lold, 0.0, lold)
   If Not IsNumeric(lnew) Then Exit Sub
   If (lnew <= 0) Or (lnew >= lold) Then Exit Sub
 
   dom = Rhino.CurveDomain(crv(0))
   If (dom(1)-crv(4)) < (crv(4)-dom(0)) Then
     Rhino.ReverseCurve crv(0)
     dom = Rhino.CurveDomain(crv(0))
   End If
 
   pts = Rhino.DivideCurveLength(crv(0), lnew)
   t = Rhino.CurveClosestPoint(crv(0), pts(1))
   Rhino.TrimCurve crv(0), Array(dom(0), t), True
 
 End Sub