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# GetMiscCellData

VTKEx/Cxx/PolyData/GetMiscCellData

Question

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### Code

GetMiscCellData.cxx

    #include <vtkSmartPointer.h>
    #include <vtkCellData.h>
    #include <vtkCellArray.h>
    #include <vtkFloatArray.h>
    #include <vtkTriangle.h>
    #include <vtkPoints.h>
    #include <vtkPolyData.h>
    #include <vtkXMLPolyDataReader.h>

    int main(int argc, char *argv[])
    {
      // Parse command line arguments
      if(argc != 3)
      {
        std::cout << "Required arguments: Filename ArrayName" << std::endl;
        return EXIT_FAILURE;
      }

      // Get filename from command line
      std::string filename = argv[1]; //first command line argument

      // Get array name
      std::string arrayName = argv[2]; //second command line argument

      //read the file
      vtkSmartPointer<vtkXMLPolyDataReader> reader =
        vtkSmartPointer<vtkXMLPolyDataReader>::New();
      reader->SetFileName(filename.c_str());
      reader->Update();

      vtkPolyData* polydata = reader->GetOutput();

      // Get the number of cells in the polydata
      vtkIdType idNumCellsInFile = polydata->GetNumberOfCells();

      vtkSmartPointer<vtkFloatArray> array =
        dynamic_cast<vtkFloatArray*>(polydata->GetCellData()->GetArray(arrayName.c_str()));

      if(array)
      {
        std::cout << "Got array " << arrayName
                  << " with " << idNumCellsInFile << " values"
                  << std::endl;
        for(int i = 0; i < idNumCellsInFile; i++)
        {
          double value;
          value = array->GetValue(i);
          std::cout << i << ": " << value << std::endl;
        }
      }
      else
      {
        std::cout << "The file " << filename
                  << " does not have a CellData array named " << arrayName
                  << std::endl;
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(GetMiscCellData)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkIOXML QUIET)
    if (NOT VTK_FOUND)
      message("Skipping GetMiscCellData: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(GetMiscCellData MACOSX_BUNDLE GetMiscCellData.cxx )
      target_link_libraries(GetMiscCellData PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(GetMiscCellData MACOSX_BUNDLE GetMiscCellData.cxx )
      target_link_libraries(GetMiscCellData PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS GetMiscCellData
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build GetMiscCellData

Click here to download GetMiscCellData and its CMakeLists.txt file. Once the tarball GetMiscCellData.tar has been downloaded and extracted,

    cd GetMiscCellData/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./GetMiscCellData

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.