偏移线中点

    Dim lineObj2 As Variant
                lineObj2 = lineObj.Offset(2 * Round(lineObj.Length, 2))

    Dim lineObj2 As Variant, lineObj3 As AcadLine
     lineObj2 = lineObj.Offset(2 * Round(lineObj.Length, 2))
       
   Dim ent As AcadEntity
       Set ent = ThisDrawing.ModelSpace(ThisDrawing.ModelSpace.Count - 1)
             If ent.ObjectName = "AcDbLine" Then
                    Set lineObj3 = ent
                    ent.Highlight True
                       Dim AA As Variant
                       Dim BB As Variant
                       Dim CC As Variant
                          AA = lineObj3.startPoint
                          BB = lineObj3.endPoint
                          CC(0) = (AA(0) + BB(0)) * 0.5
                          CC(1) = (AA(1) + BB(1)) * 0.5
                          CC(2) = (AA(2) + BB(2)) * 0.5
                          Debug.Print CC(0), CC(1), CC(2)
                   Else
            End If

    Dim lineObj2 As AcadLine
    Set lineObj2 = lineObj.Offset(-2 * Round(lineObj.Length, 2))(0) ' <-- get the first element of then variant spitted out of Offset method and set it to a line object (because you know it really is!)
   
    Dim midPoint2(0 To 2) As Double
    With lineObj2
        midPoint2(0) = (.startPoint(0) + .endPoint(0)) * 0.5
        midPoint2(1) = (.startPoint(1) + .endPoint(1)) * 0.5
        midPoint2(2) = (.startPoint(2) + .endPoint(2)) * 0.5
    End With