[vtkusers] How to really delete cells?

[Stephane PLOIX]

my_polyData is at the end of a pipeline. Each time you Update it (which is 
done at each frame if you render it), it is reset to the output of the 
previous filter.
If you want to break the dependency chain, you have to insert a 
ShallowCopy : 
output = my_vtkPolyDataConnectivityFilter->GetOutput();
my_polyData = vtkPolyData::New();
my_polyData->ShallowCopy(output);
...
and remeber to call my_polyData->Delete() later.

But the best way would be to implement a filter that does the job to 
remove some cells, so that your pipeline is still connected.

Stephane





cocoricore at gmail.com 
Envoyé par : vtkusers-bounces at vtk.org
28/07/2009 15:47

A
dominik at itis.ethz.ch
cc
vtkusers at vtk.org
Objet
Re: [vtkusers] How to really delete cells?






No change.

2009/7/28 Dominik Szczerba <dominik at itis.ethz.ch>
And what does calling ->Update() ?

Corinne Tith wrote:
Thanks for your help. I tried to put your code after 
my_polyData->RemoveDeletedCells();
Unfortunately It doesn't work.
I tried to delete lot of cells, they are never really removed.

My VTK version is 5.2, does it matter?


2009/7/28 Dominik Szczerba <dominik at itis.ethz.ch <mailto:
dominik at itis.ethz.ch>>


   my_polyData->Modified()

   Corinne Tith wrote:

       Hi all,

       I get a polydata volume with a vtkContourFilter and a
       vtkWindowSincPolyDataFilter.
       Some cells are not connected to the largest volume. They seem to
       be 'on' the mesh but have no vertice in common.

       I tried the filters vtkCleanPolyData and
       vtkPolyDataConnectivityFilter, but most of my unconnected cells
       are not removed.
       Finally, I tried to delete them 'manually', but nothing happens.

       How can I really remove my unconnected cells?

       Any help is appreciated, thanks!


       // generate my volume
      
 my_vtkWindowSincPolyDataFilter->SetInputConnection(my_vtkContourFilter->GetOutputPort());

       // no effect on my cells
      
 my_vtkCleanPolyData->SetInputConnection(my_vtkWindowSincPolyDataFilter->GetOutputPort());

       my_vtkCleanPolyData->PointMergingOn();
      
 my_vtkPolyDataConnectivityFilter->SetInputConnection(my_vtkContourFilter->GetOutputPort());
      
 my_vtkPolyDataConnectivityFilter->SetExtractionModeToLargestRegion();
       // manual remove
       my_vtkPolyDataConnectivityFilter->Update();
       my_polyData = my_vtkPolyDataConnectivityFilter->GetOutput();
       for(int i = 0; i < n; i++){
             my_polyData->DeleteCell(cellsToRemove[i]);
       }
       my_polyData->RemoveDeletedCells();


      
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