[vtkusers] how to update pipeline after changing isovalue in vtkMarchingCubes.

[Liam Kurmos]

I render a contour with vtkMarchingCubes.
I detect a keypress and the handling function creates a new instance
of vtkMarchingCubes with a different isovalue.
I call contourActor->GetMapper()->GetInput()->Update();
but i don't see any change (the old contour is still being rendered).
Do i need to somehow stop the interactor before i can update? or do i
need to update something else?

Liam

ps:
I fixed the problem i was having getting an interactorstyle
to work as an external class while having a reference to the calling class.
(i needed to #include the calling class in the .cpp file of the
interactor not the .h)