PointVisual3 not displaying points

Hi, I'm new to WPF and Helixtool kit. I wrote this code to display points cloud. The datatable contains around 100000 points and I do not see any points getting created. Appreciate any help. Thanks. 

Public Sub Create3Dviewport()

Dim pointsTable As DataTable = Get3DPoints() 'Get all point coordinates

Dim Pt3DList As Point3DCollection = New Point3DCollection

Dim pts As PointsVisual3D = New PointsVisual3D

Dim Vp3D = New Viewport3D()

Dim hVp3D = New HelixViewport3D()

For Each dr As DataRow In pointsTable.Rows

Dim pt As Point3D = New Point3D(dr(0), dr(1), dr(2))

Pt3DList.Add(pt)

Next

pts.Points = Pt3DList

pts.Size = 10

hVp3D.Children.Add(pts)

Vp3D = hVp3D.Viewport

PlotGrid.Children.Add(Vp3D)

End Sub