[vtkusers] Memory leaks using vtk filters

[Hans Gruendel]

Hello All,

after using vtk quite often in complex projects I run into trouble with 
memory leaks. Thus my question is:

How to reuse data produced by vtkAlgorithms after having deleted the 
producing algorithm?

Is the following procedure right?

vtkPolyData * UtilsClass::cutIsoValue(vtkUnstructuredGrid Block, double 
IsoValue)
{
  vtkContourFilter * cF = vtkContourFilter::New();
  cF->SetInputConnection(Block->GetProducerPort());
  cF->SetValue(0,IsoValue);
  cF->Update();

  vtkPolyData * PolyData = vtkPolyData::New();
  PolyData->ShallowCopy( cF->GetOutput() );

  cF->Delete();

  return PolyData;
}

and the calling function
{
vtkPolyData* ResultPolyData = UtilsClass::cutIsoValue(Block, Isovalue);
..and later..
ResultPolyData->Delete();
}

I suspect memory leaks using this procedure.
- What is happening with the cF->GetOutput()? Is all the working data of 
cF really deleted?
- Is everything properly deleted at the end of the calling function?
- What would be the proper manner?
- Could a method from the vtkobject class solve the problem?


Thanks for your help in advance.

Greetings Hans