# ExtractFaces

VTKExamples/Cxx/Utilities/ExtractFaces

### Code

ExtractFaces.cxx

    #include <vtkSmartPointer.h>
    #include <vtkCellIterator.h>
    #include <vtkGenericDataSet.h>
    #include <vtkGenericCell.h>
    #include <vtkXMLGenericDataObjectReader.h>
    #include <vtkPointSet.h>
    #include <vtkCellTypes.h>

    #include <map>

    int main (int argc, char *argv[])
    {
      std::map<std::string, int> cellMap;

      for (int arg = 1; arg < argc; ++arg)
      {
        vtkSmartPointer<vtkXMLGenericDataObjectReader> reader =
          vtkSmartPointer<vtkXMLGenericDataObjectReader>::New();
        reader->SetFileName(argv[arg]);
        reader->Update();

        vtkPointSet *pointSet = vtkPointSet::SafeDownCast(reader->GetOutput());
        vtkCellIterator *it = pointSet->NewCellIterator();
        for (it->InitTraversal(); !it->IsDoneWithTraversal(); it->GoToNextCell())
        {
          vtkSmartPointer<vtkGenericCell> cell =
            vtkSmartPointer<vtkGenericCell>::New();
          it->GetCell(cell);
          std::string cellName = vtkCellTypes::GetClassNameFromTypeId(cell->GetCellType());
          if (cellMap.count(cellName) == 0)
          {
            int numFaces = cell->GetNumberOfFaces();
            std::cout << "Type: " << cellName
                      << " has " << cell->GetNumberOfFaces() << " faces" << std::endl;
          }
          cellMap[cellName]++;
        }
    }
      std::map <std::string, int>::iterator itm = cellMap.begin();

      for (itm = cellMap.begin(); itm != cellMap.end(); ++itm)
      {
        std::cout << itm->first << " occurs " << itm->second << " times" << std::endl;
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ExtractFaces)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(ExtractFaces MACOSX_BUNDLE ExtractFaces.cxx )

    target_link_libraries(ExtractFaces ${VTK_LIBRARIES})

### Download and Build ExtractFaces

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

    cd ExtractFaces/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:

    ./ExtractFaces

WINDOWS USERS

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