[vtkusers] Pattented contouring filters in vtk

[Robert Milaszewski]

We are using version 4.3 of vtk release.  I see a few contouring filters
in Patented subdirectory of the vtk distribution.  I also noticed that newer
versions of vtk have these filters in Graphics subdirectory.  Does that mean
that patents expired on these contouring algorithms.  What is the 
current status
and how does it affect version of vtk that we are using?

thanks,
Robert M Milaszewski