Option Explicit

'In: lines, box
'Out: boxes copied and rotated to each line

Sub OrientBoxes
  
  Dim arrLines, strBox, arrRefPoints, arrTargetPoints(1), i
  
  arrLines = Rhino.GetObjects("Select the intersection lines", 4)
  
  strBox = Rhino.GetObject("Select the box to copy to each line", 4)
  
  arrRefPoints = Rhino.GetPoints(True,,"Select the 1st reference point","Select the 2nd reference point", 2)
  
  For i = 0 To UBound(arrLines)
    Rhino.StatusBarMessage i & "/" & UBound(arrLines)
    arrTargetPoints(0) = Rhino.CurveMidPoint(arrLines(i))
    arrTargetPoints(1) = Rhino.CurveStartPoint(arrLines(i))
    Rhino.OrientObject strBox, arrRefPoints, arrTargetPoints,1
  Next
  
End Sub

OrientBoxes