'This is sample code to illustrate ITransform2D Interface. Load polygon feature class
' in MXD as first layer. Select one polygon and run this code in VBA. This code may be 
'efficient or handle any bugs.THIS IS FOR SAMPLE ONLY. Author is not responsible for dataloss
' or any other issues. Please take backup of your data, before you try. 

Dim pMxdocument As IMxDocument




Sub Main()
Dim pTransform As ITransform2D
Dim pPolygon As IPolygon
Dim pFSel As IFeatureSelection
Dim pSelSet As ISelectionSet
Dim pFeature As IFeature
Dim sLayerName As String
Dim pFCursor As IFeatureCursor
Set pMxdocument = ThisDocument
Set pMapLayer = pMxdocument.FocusMap.Layer(0)
If pFeature Is Nothing Then
Set pFSel = pMapLayer
Set pSelSet = pFSel.SelectionSet
pSelSet.Search Nothing, False, pFCursor
Set pFeature = pFCursor.NextFeature
pMxdocument.FocusMap.ClearSelection
End If

Set pPolygon = pFeature.Shape
Call RotatePoly(pPolygon, 45)
pFeature.Store

End Sub

  




Sub RotatePoly(pPolygon As IPolygon, dAng As Double)
 
 Dim pArea As IArea
 Dim pOrigin As IPoint
 Dim dAngle As Double
 Dim pTransform As ITransform2D
 Dim Pi As Double
 Dim pRotationEnvelop As IEnvelope
 
 Set pMxdocument = ThisDocument
 Set pMapLayer = pMxdocument.FocusMap.Layer(0)
 Set pRotationEnvelop = New Envelope
 
  Pi = 4 * Atn(1)
  dAngle = dAng * Pi / 180
  If (Not pPolygon.IsEmpty) Then
    Set pArea = pPolygon
    Set pOrigin = pArea.Centroid
    Set pTransform = pPolygon
    pTransform.Rotate pOrigin, dAngle
    Set pRotationEnvelop = pPolygon.Envelope
    pMxdocument.ActiveView.PartialRefresh esriViewGeography, pMapLayer, pRotationEnvelop
    pMxdocument.ActiveView.PartialRefresh esriViewGeoSelection, pMapLayer, pRotationEnvelop
  End If
  
End Sub