[vtkusers] ExtractSelectedThresholds

[David Doria]

On Tue, Apr 27, 2010 at 7:45 PM, David E DeMarle
<dave.demarle at kitware.com> wrote:
> Yep, you need to tell the SelectionNode that its contents describe a
> set of thresholds, since otherwise they might represent a set of ids,
> locations etc.
>
> That flag is used as a sanity check in the Extraction filters and more
> to the point by the vtkExtractSelection filter, which uses it to
> decide which of the real ExtractionFilters it needs to call into for
> any given SelectionNode. That is why you don't see
> vtkExtractSelectedThresholds instantiated by name in that test.


Almost there...

I did what you said:
selectionNode->SetContentType(vtkSelectionNode::THRESHOLDS);

I also added:
selectionNode->SetSelectionData(selectEnclosedPoints->GetOutput()->GetPointData());

But now the error is:
vtkExtractSelectedThresholds (0x8de7b88): Could not figure out what
array to threshold in.

I think we really need an updated version of a tutorial on "How
selections work", these things seem quite confusing.

Thanks,

David