通過設置圓和圓弧實體的Center、Radius屬性，可以改變其圓心坐標和半徑值，通過返回其屬性值，可以獲取其圓心坐標和半徑值。

下面的代碼將模型空間的所有圓向上移動100的單位，并將半徑減為原來的一半。

Private Sub Command1_Click()
    Dim i As Integer
    Dim currcenterpt As Variant
    Dim newcenterpt(0 To 2) As Double
    Dim rad As Double
    For i = 0 To acadapp.ActiveDocument.ModelSpace.Count – 1
        If acadapp.ActiveDocument.ModelSpace(i).EntityType = acCircle Then
            currcenterpt = acadapp.ActiveDocument.ModelSpace(i).center
            rad = acadapp.ActiveDocument.ModelSpace(i).radius
            newcenterpt(0) = currcenterpt(0)
            newcenterpt(1) = currcenterpt(1) + 100
            newcenterpt(2) = currcenterpt(2)
            rad = rad / 2
            acadapp.ActiveDocument.ModelSpace(i).center = newcenterpt
            acadapp.ActiveDocument.ModelSpace(i).radius = rad
            acadapp.ActiveDocument.ModelSpace(i).Update
        End If
    Next i
End Sub