[vtkusers] cuting a dataset with holes in it

[Galina Atanasova]

I have a problem filling the plane ones I cut it. I am cutting
polydata (unstructured grid).
Imagine you have a bagel for breakfast, you cut it and then when you
want to put the cheese on top, with VTK you do not know if there is a
hole, which part is the hole and so on.
Do you know how I can define it?
I could not find any class that would be able to define in and out in
some way, the only thing vtkTriangleFilter does is fill in between the
points and even that is not done as good as it should be.
Any help will be greatly appreciated!