what procedure do you use for drawing a polyline with arcs in it. I am trying to learn vb.net latest version

I can draw a polyline using these 2 methods but if I try to add a bulge as per the VBA example in the sdk I am getting an error.

'draw polyline

Dim poly As IMSIGX.Graphic

poly = TCDraw.Graphics.AddLineMultiline(0, 0, 0)

poly.Vertices.UseWorldCS = True

poly.Vertices.Add(0, 500, 0)

poly.Vertices.Add(600, 600, 0)

poly.Vertices.AddClose()

poly.Draw()

End Sub

Private Sub Button6_Click(sender As Object, e As EventArgs) Handles Button6.Click

Dim poly As IMSIGX.Graphic

poly = TCDraw.Graphics.Add(, "TCW50Polyline")

poly.Vertices.UseWorldCS = True

poly.Vertices.Add(0, 0, 0)

poly.Vertices.Add(5, 0, 0)

poly.Vertices.Add(5, 2.5, 0) 'arc centre

'poly.Vertices.Add.Bulge = True

poly.Vertices.Add(7.5, 2.5, 0)

'poly.Vertices.Add.Bulge = True

poly.Vertices.Add(5, 5, 0)

'poly.Vertices.Add.Bulge = False

poly.Vertices.Add(0, 5, 0)

poly.Draw()

the example in the sdk

'Add an arc "bulge" segment.

'First specify the arc's center, then a pass-through point.

'Set vx = verts.Add (5, 2.5, 0) arc center'

'vx.Bulge = True

'set vx = verts.Add(7.5, 2.5, 0)

'arc pass-through

'vx.Bulge = True

'Set vx = verts.Add (5, 5, 0)

'end of arc segment'vx.Bulge = False

'verts.Add 0, 5, 0, False

'hide this segment by setting PenDown to False'verts.AddClose True

'close the polyline and show the last segment

'grf.Draw

Nikki

TC20 platinum

TC 2015 platinum

TC 2017 with lightworks