[vtkusers] vtkPolyDataConnectivityFilter question about extracted region id's

[Berk Geveci]

>From vtkPolyDataConnectivityFilter.cxx:

  // Traverse all cells marking those visited.  Each new search
  // starts a new connected region. Connected region grows 
  // using a connected wave propagation.

Since each cell is visited in order, the id of a region depends on it's
cell with the smallest id. For example, the region which contains cell 0
will be region 0.

-Berk

On Tue, 2003-12-30 at 14:00, Aysegul Gunduz wrote:
> Hi all,
> 
> I was wondering how the extracted regions are given their region ids.  Is 
> there some kind of convention?
> Or in other words how do I know the id of the region I want to add?
> Thanks,
> 
> A Gunduz
> 
> Hi Audrius -
> 
> At 01:00 PM 4/20/2001 -0400, you wrote:
> 
> >aContourTestPolyData = aConnectivityFilter->GetOutput( iContourRegion);
> 
> The filter produces a single output. Normally you set the mode of the
> filter to extract a specified region (or regions) and then grab the output
> similar to:
> 
> aConnectivityFilter = vtkPolyDataConnectivityFilter::New();
> aConnectivityFilter->SetInput( aContourMarchingSquares->GetOutput() );
> aConnectivityFilter->ScalarConnectivityOff();
> aConnectivityFilter->SetExtractionModeToSpecifiedRegions();
> aConnectivityFilter->InitializeSpecifiedRegionList();
> aConnectivityFilter->AddSpecifiedRegion(iContourRegion);
> aConnectivityFilter->Update();
> 
> vtkPolyData *aContourTestPolyData = aConnectivityFilter->GetOutput();
> 
> Will
> 
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-- 
Berk Geveci <berklist at nycap.rr.com>