Hi Jaap, Lists are different from arrays. Either use one or use the other (I recommend using lists). Try the following:
Dim listA As New List(Of Integer) For i As Integer = 0 To all.Count-2 For n As Integer = 0 To endchord.Count-1 If (endchord(n).DistanceTo(all(i)) < 1e-32) Then ListA.Add(i) End If Next Next A = listA -- David Rutten da...@mcneel.com Robert McNeel & Associates