Draw circle using Flatten function

Question

I'm curently implementing a circle visualization using X points in Input.

I don't know if it's the best way (do not hesitate to tell me about any other possibility) but to realize that, i'm creating a Path with these differents points and then i use the "Flatten" function to smooth the curve :

For Each Point As Point3D In ptsLocal
            graphic_points(index).X = (panel.Width / 2) + (Point.z * facteur)
            graphic_points(index).Y = (panel.Width / 2) - (Point.y * facteur)
            Draw_ringPoint(graphic, Brushes.Gray, graphic_points(index).X, graphic_points(index).Y, 4, IdsPts(index))
            index += 1
        Next
        graphic_points(index).X = graphic_points(0).X
        graphic_points(index).Y = graphic_points(0).Y
        Dim myPath As New GraphicsPath

        'Dim translateMatrix As New Matrix
        'translateMatrix.Translate(0, 10)

        myPath.AddCurve(graphic_points)
        'graphic.DrawPath(New Pen(Color.Cyan, 2), myPath)
        myPath.Flatten()
graphic.DrawPath(New Pen(Color.BlueViolet, 2), myPath)

As you can see, I add the point "0" at the end to close the curve, here is my result :

as you can see, the result is good, except the connection between the last point and the first point.

How can i smooth this connection ? Or there is any other solution to realize this visualization ?

EDIT :

After using the DrawClosedCurve method, the result look better, but still have a problem on the last connection as you can see (With the last connection point):

And without the last connection point :