Here is a RhinoScript based on Newton’s Method: http://www.1728.org/newton.htm

NewtonsArc.rvb (883 Bytes)

Please let me know of any changes required or if you need this converted to Python.

Keith www.cadwax.com

(UK Rhino Reseller / Scripting and Support)

```
Option Explicit
'Script written by <Keith Reffell>
'Script copyrighted by <www.cadwax.com>
'Script version 23 May 2016 07:55:53
Call Main()
Sub Main()
Dim arc
arc = rhino.GetReal("Enter Arc length") / 2
If isNull(arc) Then
Exit Sub
End If
Dim chord
chord = rhino.GetReal("Enter Chord length") / 2
If isNull(chord) Then
Exit Sub
End If
Dim n
n = chord / arc
Dim x1
x1 = 1 - ((Sin(1) - (n * 1)) / (Cos(1) - n))
Dim x2
x2 = x1 - ((Sin(x1) - (n * x1)) / (Cos(x1) - n))
Do While round(x1, 6) <> round(x2, 6)
x1 = x2
x1 = x1 - ((Sin(x1) - (n * x1)) / (Cos(x1) - n))
x2 = x1 - ((Sin(x1) - (n * x1)) / (Cos(x1) - n))
Loop
Dim radius
radius = chord / Sin(x2)
rhino.Command "_Arc _StartPoint _Pause " & Chord * 2 & " _Pause _Radius " & Radius
End Sub
```