RectilinearGridToTetrahedra

#include <vtkSmartPointer.h>
#include <vtkXMLUnstructuredGridWriter.h>
#include <vtkRectilinearGrid.h>
#include <vtkRectilinearGridToTetrahedra.h>
#include <vtkUnstructuredGrid.h>
#include <vtkMath.h>
#include <vtkDoubleArray.h>

int main(int, char *[])
{
  // Create a grid
  vtkSmartPointer<vtkRectilinearGrid> grid = 
    vtkSmartPointer<vtkRectilinearGrid>::New();

  grid->SetDimensions(5,4,3);

  vtkSmartPointer<vtkDoubleArray> xArray = 
    vtkSmartPointer<vtkDoubleArray>::New();
  xArray->InsertNextValue(0.0);
  xArray->InsertNextValue(1.0);
  xArray->InsertNextValue(2.0);
  xArray->InsertNextValue(3.0);
  xArray->InsertNextValue(4.0);

  vtkSmartPointer<vtkDoubleArray> yArray = 
    vtkSmartPointer<vtkDoubleArray>::New();
  yArray->InsertNextValue(0.0);
  yArray->InsertNextValue(1.0);
  yArray->InsertNextValue(2.0);
  yArray->InsertNextValue(3.0);

  vtkSmartPointer<vtkDoubleArray> zArray = 
    vtkSmartPointer<vtkDoubleArray>::New();
  zArray->InsertNextValue(0.0);
  zArray->InsertNextValue(1.0);
  zArray->InsertNextValue(2.0);

  grid->SetXCoordinates(xArray);
  grid->SetYCoordinates(yArray);
  grid->SetZCoordinates(zArray);

  vtkSmartPointer<vtkRectilinearGridToTetrahedra> rectilinearGridToTetrahedra =
    vtkSmartPointer<vtkRectilinearGridToTetrahedra>::New();
  rectilinearGridToTetrahedra->SetInputData(grid);
  rectilinearGridToTetrahedra->Update();

  vtkSmartPointer<vtkXMLUnstructuredGridWriter> writer = 
    vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
  writer->SetFileName("output.vtu");
  writer->SetInputConnection(rectilinearGridToTetrahedra->GetOutputPort());
  writer->Write();

  std::cout << "There are " 
            << rectilinearGridToTetrahedra->GetOutput()->GetNumberOfCells()
            << " cells." << std::endl;

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(RectilinearGridToTetrahedra)

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

cd RectilinearGridToTetrahedra/build 

cmake ..

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

make

./RectilinearGridToTetrahedra