[vtkusers] Re: file format conversion (XML <-> simple legacy format)

[Amy Squillacote]

Hi M.B.,

Using the legacy VTK writers (e.g., vtkPolyDataWriter, 
vtkUnstructuredGridWriter, etc.), if you want to have more than one 
scalar, vector, etc. array, arrays beyond the first one must be 
stored in field data. Try calling GetNumberOfFieldDataInFile(); it 
should account for your "missing" arrays.

(At the time these writers were written, this mirrored the structure 
of vtkPointData / vtkCellData.) Using the VTK XML writers, you can 
certainly store more than one of any given type of array.

- Amy

At 01:20 PM 5/25/2006, Martin Baumann wrote:
>Is it generally possible to save more than one scalar / vector into 
>one file using vtk's writers?
>It seems to me as if one could only save ONE scalar / vector.
>
>Regards, M.B.
>
>
>Martin Baumann schrieb:
>
>>Hi,
>>
>>I just realized, that I have the same problem using 
>>vtkUnstructuredGridReader and vtkUnstructuredGridWriter:
>>
>>  // read orginal file
>>  vtkUnstructuredGridReader*    _grid_reader      = 
>> vtkUnstructuredGridReader::New();
>>  _grid_reader->SetFileName(in_file.c_str());
>>  _grid_reader->Update();
>>  cout << "#Points : " << 
>> _grid_reader->GetOutput()->GetNumberOfPoints() << endl;
>>  cout << "#Scalars: " << _grid_reader->GetNumberOfScalarsInFile() << endl;
>>
>>  // writer new file
>>  vtkUnstructuredGridWriter* _grid_writer  = 
>> vtkUnstructuredGridWriter::New();
>>  _grid_writer->SetFileName("camembert.new.hvs");
>>  _grid_writer->SetInput(_grid_reader->GetOutput());
>>  _grid_writer->Write();
>>
>>  // read new file
>>  _grid_reader->SetFileName("camembert.new.hvs");
>>  _grid_reader->Update();
>>  cout << "#Points : " << 
>> _grid_reader->GetOutput()->GetNumberOfPoints() << endl;
>>  cout << "#Scalars: " << _grid_reader->GetNumberOfScalarsInFile() << endl;
>>
>>
>>This makes the following output:
>>
>>  #Points : 400
>>  #Scalars: 3
>>  #Points : 400
>>  #Scalars: 1
>>
>>Hmmm....
>>
>>Regards, M.B.
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