半徑或直徑型尺寸標注用來標注圓或圓弧，半徑或直徑型標注的類型與圓或圓弧的大小，TextPosition屬性有關也與尺寸標注系統變量DIMUPT、DIMTOFL、DIMTIH、DIMTOH、DIMJUST、DIMTAD的值有關，系統變量用GetVariable和SetVariable方法返回。

創建半徑型尺寸標注對象用AddDimRadial方法，語法格式如下。

RetVal=object.AddDimRadial(Center,ChordPoint,LeaderLength)

創建直徑型尺寸標注對象用AddDimRadial方法，語法格式如下。

RetVal=object.AddDimDiametric(ChordPoint,FarChordPoint,LeaderLength)

下面的代碼創建一個直徑型尺寸標注。

Private Sub Command1_Click()
    Dim circleobj As AcadCircle
    Dim centerpoint(0 To 2) As Double
    Dim radius As Double
    centerpoint(0) = 10#: centerpoint(1) = 5#: centerpoint(2) = 0#
    radius = 5
    Set circleobj = acadapp.ActiveDocument.ModelSpace.AddCircle(centerpoint, radius)
    Dim dimobj As AcadDimDiametric
    Dim chordpoint(0 To 2) As Double
    Dim farchordpoint(0 To 2) As Double
    Dim leaderlength As Double
    chordpoint(0) = 15#: chordpoint(1) = 5#: chordpoint(2) = 0
    farchordpoint(0) = 5#: farchordpoint(1) = 5#: farchordpoint(2) = 0#
    leaderlength = 1#
    Set dimobj = acadapp.ActiveDocument.ModelSpace.AddDimDiametric(chordpoint, farchordpoint, leaderlength)
    ZoomExtents
End Sub