[vtkusers] question about vtkPolyDataConnectivityFilter

[Anja Ende]

Hi Mike,

Thanks for your reply! I did as you had suggested but am having
problems as follows:

int npts, *pts;
int numCells = polyData->GetLines()->GetNumberOfCells();
while (polyData->GetLines()->GetNextCell(npts,pts) )
{
	for (int j = 0; j < npts; ++j)
	{
		vtkCell * cell = ....
        }
}

How can I now access the current cell. I ran this through the debugger
and I can see that the number of points returned by GetNextCell() is
2. However, I am not sure how I can now access these coordinates! Any
ideas?

Thanks,

Anja

On 05/04/2008, Mike Jackson <imikejackson at gmail.com> wrote:
> You also want to add:
>
>  polyDataFilter->SetExtractionModeToAllRegions();
>
>  After you run the filter the first time then you will run it in a loop,
> each time through the loop you set:
>  for (int i = 0; i < numRegions; ++i)
>  {
>  polyDataFilter->InitializeSpecifiedRegionList ()
>  polyDataFilter->AddSpecifiedRegion (i);
>  polyDataFilter->SetInput(contourFilter->GetOutput());
>  polyDataFilter->SetScalarRange(255.0, 255.0);
>  polyDataFilter->Update();
>  vtkPolyData* polyData = polYDataFilter->getOUtput();
>  }
>
>  That is only one way and it has been a while since I have had to do
> something like this. There may be newer/faster ways.
>
>  The way we solved it was to re-write the vtkPolYDataConnectivityFilter to
> actually extract all the regions and store them in a vtkPolyDataCollection.
> This proved the fastest for us.
>
>  Our code can be found here:
> http://titanium.imts.us/viewvc/Task_4/Mesher/DNAPolyDataConnectivityFilter.cpp?view=log
> http://titanium.imts.us/viewvc/Task_4/Mesher/DNAPolyDataConnectivityFilter.h?view=log
>
>  They may need to be updated for vtk 5.x but you are welcome to use the
> code.
>
>  --
>  Mike Jackson   Senior Research Engineer
>  Innovative Management & Technology Services
>
>
>
>  On Apr 5, 2008, at 7:27 AM, Anja Ende wrote:
>
> >
> > Hi everyone,
> >
> > I am using vtkPolyDataConnectivityFilter as follows:
> >
> > vtkContourFilter * contourFilter = vtkContourFilter::New();
> > contourFilter->SetInput(vtkDicomReader->GetOutput());
> > contourFilter->SetValue(0, 255);
> >
> > vtkPolyDataConnectivityFilter * polyDataFilter =
> > vtkPolyDataConnectivityFilter::New();
> > polyDataFilter->SetInput(contourFilter->GetOutput());
> > polyDataFilter->SetScalarRange(255.0, 255.0);
> > polyDataFilter->Update();
> >
> > int regions =
> polyDataFilter->GetNumberOfExtractedRegions();
> >
> > Now what I want to do is iterate through all the regions and each of
> > the points in the region. However, I cannot figure out how to do this.
> > Anyone has any idea on how I can iterate through the regions and the
> > points?
> >
> > Cheers,
> >
> > Anja
> > _______________________________________________
> > This is the private VTK discussion list.
> > Please keep messages on-topic. Check the FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
> > Follow this link to subscribe/unsubscribe:
> > http://www.vtk.org/mailman/listinfo/vtkusers
> >
>
>


-- 
Cheers,

Anja