[abenedik]

I do not know what could cause that error.

I have tried again with using the following VB code and it worked well:

Code:

   Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs)
       Dim camera As New Ab3d.Cameras.TargetPositionCamera
       Dim viewCube As New Ab3d.Controls.ViewCubeCameraController
       viewCube.TargetCamera = camera
       RootGrid.Children.Add(viewCube)
   End Sub

Could you share a small code snipper that could reproduce that error. Also please tell which version of Ab3d.PowerToys do you use - the one from the installer or from NuGet and which version of .Net Framework / .Net Core are you using.