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

[Liam Kurmos]

> The normal VTK way of doing this is to instantiate a single pipeline
> and modify only the existing objects (meaning that you shouldn't
> create a new vtkMarchingCubes object).  So when you want to change the
> isovalue, just call:
>
> marchingCubes->SetIsovalue(...);
> marchingCubes->Update();
> renderWindow->Render();
>
> The update should propagate down the pipeline and update everything
> that needs to get updated.
>
> David
>

Excellent, it works. Thanks David!

Getting the hang of vtk now slowly,

Liam