<CommandMethod("BBO")> _
    Public Sub testBlockBound()
        Dim doc As Document = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument
        Dim db As Database = doc.Database
        Dim ed As Editor = doc.Editor
        'Matrix3d ucs = ed.CurrentUserCoordinateSystem;
        Dim clon As BlockReference = Nothing
        doc.TransactionManager.EnableGraphicsFlush(True)
        Try
            Dim peo As New PromptEntityOptions(vbLf & "Select block: ")
            peo.SetRejectMessage("Only a block instance !")
            peo.AddAllowedClass(GetType(BlockReference), False)
            Dim per As PromptEntityResult = ed.GetEntity(peo)
            If per.Status <> PromptStatus.OK Then
                Return
            End If
            Dim id As ObjectId = per.ObjectId
            Using tr As Transaction = db.TransactionManager.StartTransaction()
                Dim ent As Entity = CType(tr.GetObject(id, OpenMode.ForRead), Entity)
                If ent Is Nothing Then
                    Return
                End If
                Dim bref As BlockReference = TryCast(ent, BlockReference)
                If bref Is Nothing Then
                    Return
                End If
                clon = TryCast(bref.Clone(), BlockReference)
                clon.Rotation = 0
                clon.TransformBy(ed.CurrentUserCoordinateSystem)
                tr.TransactionManager.QueueForGraphicsFlush()
                Dim ext As Extents3d = clon.GeometryExtentsBestFit(ed.CurrentUserCoordinateSystem)
                ext.TransformBy(ed.CurrentUserCoordinateSystem)
                Dim pl As New Polyline(4)
                Dim p1 As Point3d = ext.MinPoint.TransformBy(ed.CurrentUserCoordinateSystem)
                Dim p3 As Point3d = ext.MaxPoint.TransformBy(ed.CurrentUserCoordinateSystem)
                Dim p2 As Point3d = New Point3d(p3.X, p1.Y, p1.Z).TransformBy(ed.CurrentUserCoordinateSystem)
                Dim p4 As Point3d = New Point3d(p1.X, p3.Y, p1.Z).TransformBy(ed.CurrentUserCoordinateSystem)
                pl.AddVertexAt(0, New Point2d(p1.X, p1.Y), 0.0, 0.0, 0.0)
                pl.AddVertexAt(1, New Point2d(p2.X, p2.Y), 0.0, 0.0, 0.0)
                pl.AddVertexAt(2, New Point2d(p3.X, p3.Y), 0.0, 0.0, 0.0)
                pl.AddVertexAt(3, New Point2d(p4.X, p4.Y), 0.0, 0.0, 0.0)
                pl.Closed = True
                pl.ColorIndex = 121
                pl.TransformBy(ed.CurrentUserCoordinateSystem)
                Dim rot As Matrix3d = Matrix3d.Rotation(bref.Rotation, bref.Normal.GetNormal(), bref.Position)
                pl.TransformBy(rot)
                Dim btr As BlockTableRecord = CType(tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite), BlockTableRecord)
                btr.AppendEntity(pl)
                tr.AddNewlyCreatedDBObject(pl, True)
                tr.TransactionManager.QueueForGraphicsFlush()
                doc.TransactionManager.FlushGraphics()
                tr.Commit()
            End Using
        Catch e As System.Exception
            ed.WriteMessage(vbLf & "Error: {0}" & vbLf & "{1}", e.Message, e.StackTrace)
        Finally
            If Not clon.IsDisposed Then
                clon.Dispose()
                'optional
            End If
        End Try
    End Sub