You can directly renumber the entities within Staad by the RENUMBER option. see below.
However, if you want a MACRO by which you can instruct to renumber any particular entity then there is no such direct Open-Staad Function available which can RENUMBER or REPLACE the entity number. However, you can indirectly renumber any specific entity like node, beam, plate by first deleting the target entity and then create a new entity at the same location with a new numbering.
But there are several limitations. For example when you are deleting a node and then again creating new node then the connected members and its properties , the imposed loading etc get deleted. So, it is a very uphill task to again re-create the deleted beams and then assign different specification and loading.
The following VBA code may help in renumbering a particular node.
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Dim objOpenSTAAD As Object
Dim NodeNo As Long
Dim a As Long
Dim b As Long
Dim MemberNo As Long
Dim NodeA As Long
Dim NodeB As Long
Dim CoordX As Double
Dim CoordY As Double
Dim CoordZ As Double
Set objOpenSTAAD = GetObject(, "StaadPro.OpenSTAAD")
a = Application.InputBox(prompt:="enter the target node", Type:=3)
b = Application.InputBox(prompt:="enter the renumbered node", Type:=3)
NodeNo = a
objOpenSTAAD.Geometry.GetNodeCoordinates NodeNo, CoordX, CoordY, CoordZ
objOpenSTAAD.Geometry.DeleteNode NodeNo
objOpenSTAAD.Geometry.CreateNode b, CoordX, CoordY, CoordZ
End Sub
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The .xlsm file is attached herewith.
Using the same approach you can renumber a member and a plate.
(Please visit the site to view this file)