[vtkusers] vtkExtractEdges changes point IDs?

[David Doria]

> VTK filters are not guaranteed to output the same IDs for points as
> their inputs.  In particular, any filters that extract just part of
> the input geometry will usually throw away any points that aren't part
> of the output geometry.
>
> Also, most filters will merge points that are coincident, i.e. if two
> inputs points are at exactly the same position in the input then they
> will often be merged in the output.
>
>   David
>

In this case, there are no coincident points and all input points are
passed to the output. Apparently they are still not guaranteed to have
the same ID. Is this accurate?

Thanks,

David