VTK reads the whole file instead of the selected array.

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The following code requests the “Q” scalar field to be read only, but VTK nevertheless attempts to read the whole thing, saturating 256GB of memory, and crashing. Is there something I am doing wrong?

#include <cstdint>
#include <string>

#include <vtkDataObject.h>
#include <vtkResampleToImage.h>
#include <vtkSmartPointer.h>
#include <vtkXMLImageDataWriter.h>
#include <vtkXMLUnstructuredGridReader.h>

// Usage: ./vtu_to_vti_converter [VTU_FILEPATH] [X_RESOLUTION] [Y_RESOLUTION] [Z_RESOLUTION].
std::int32_t main(std::int32_t argc, char** argv)
{
  auto filepath  = std::string(argv[1]);

  auto reader    = vtkSmartPointer<vtkXMLUnstructuredGridReader>::New();
  auto converter = vtkSmartPointer<vtkResampleToImage>          ::New();
  auto writer    = vtkSmartPointer<vtkXMLImageDataWriter>       ::New();

  reader   ->SetFileName           (filepath.c_str());
  reader   ->SetInputArrayToProcess(0, 0, 0, vtkDataObject::FIELD_ASSOCIATION_CELLS, "Q");

  converter->SetInputConnection    (reader->GetOutputPort());
  converter->SetUseInputBounds     (true);
  converter->SetSamplingDimensions (std::stoi(argv[2]), std::stoi(argv[3]), std::stoi(argv[4]));

  writer   ->SetInputConnection    (converter->GetOutputPort());
  writer   ->SetFileName           ((filepath.substr(0, filepath.size() - 3) + std::string("vti")).c_str());
  writer   ->Update                ();

  return 0;
}