How can one get the size of a selected subPath without breaking apart?

Simply try:

Sub Test()

Dim OriUnit As Long

OriUnit = ActiveDocument.Unit
ActiveDocument.Unit = cdrInch

' ....

ActiveDocument.Unit = OriUnit

End Sub

Thanks, NudeFan, didn't think about mm conversion. Got it. How can I reduce the number of decimal places to three?

msgbox Format(w, "0.000")

or: MsgBox "Width = " + Format(W, "0.000")

Thanks all, this is where I'm leaving it

Sub SubPathSize()
Dim OS As Shape, x#, y#, w#, h#
Dim OriUnit As Long
OriUnit = ActiveDocument.Unit
ActiveDocument.Unit = cdrInch
Set OS = ActiveSelection.Shapes(1)
For i = 1 To OS.Curve.Segments.Count
If OS.Curve.Segments(i).Selected = True Then
OS.Curve.Segments(i).GetBoundingBox x, y, w, h
MsgBox ("Width = " + Format(w, "0.000") & vbCr & "Height = " + Format(h, "0.000") & vbCr)
End If
Next i
ActiveDocument.Unit = OriUnit
End Sub