ExtractFaces

VTKExamples/Cxx/Utilities/ExtractFaces

Question

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Code

ExtractFaces.cxx

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

#include <map>

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

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

    //    vtkPointSet *pointSet =
    //    vtkPointSet::SafeDownCast(reader->GetOutput());;
    vtkPointSet* pointSet = dynamic_cast<vtkPointSet*>(reader->GetOutput());
    ;
    auto it = pointSet->NewCellIterator();
    for (it->InitTraversal(); !it->IsDoneWithTraversal(); it->GoToNextCell())
    {
      auto cell = vtkSmartPointer<vtkGenericCell>::New();
      it->GetCell(cell);
      std::string cellName =
          vtkCellTypes::GetClassNameFromTypeId(cell->GetCellType());
      if (cellMap.count(cellName) == 0)
      {
        std::cout << "Type: " << cellName << " has " << cell->GetNumberOfFaces()
                  << " faces" << std::endl;
      }
      cellMap[cellName]++;
    }
    it->Delete();
  }
  for (auto 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 3.3 FATAL_ERROR)

project(ExtractFaces)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  vtkIOXML QUIET)
if (NOT VTK_FOUND)
  message("Skipping ExtractFaces: ${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(ExtractFaces MACOSX_BUNDLE ExtractFaces.cxx )
  target_link_libraries(ExtractFaces PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ExtractFaces MACOSX_BUNDLE ExtractFaces.cxx )
  target_link_libraries(ExtractFaces PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ExtractFaces
    MODULES ${VTK_LIBRARIES}
    )
endif () 

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.