Only linear and angular general dimensions are supported. Open a drawing document that contains several dimensions and run the sample.
Public Sub CenterAllDimensions()
' Set a reference to the active drawing document
Dim oDoc As DrawingDocument
Set oDoc = ThisApplication.ActiveDocument
' Set a reference to the active sheet
Dim oSheet As Sheet
Set oSheet = oDoc.ActiveSheet
Dim oDrawingDim As DrawingDimension
' Iterate over all dimensions in the drawing and
' center them if they are linear or angular.
For Each oDrawingDim In oSheet.DrawingDimensions
If TypeOf oDrawingDim Is LinearGeneralDimension Or _
TypeOf oDrawingDim Is AngularGeneralDimension Then
Call oDrawingDim.CenterText
End If
Next
End Sub