Hexahedron

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkCellArray.h>
#include <vtkDataSetMapper.h>
#include <vtkHexahedron.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkUnstructuredGrid.h>

#include <array>
#include <vector>

int main(int, char*[])
{

  vtkNew<vtkNamedColors> colors;

  // Set the background color.
  std::array<unsigned char, 4> bkg{{51, 77, 102, 255}};
  colors->SetColor("BkgColor", bkg.data());

  // For the hexahedron; setup the coordinates of eight points.
  // The two faces must be in counter clockwise order as viewed from the
  // outside.
  std::vector<std::array<double, 3>> pointCoordinates;
  pointCoordinates.push_back({{0.0, 0.0, 0.0}}); // Face 1
  pointCoordinates.push_back({{1.0, 0.0, 0.0}});
  pointCoordinates.push_back({{1.0, 1.0, 0.0}});
  pointCoordinates.push_back({{0.0, 1.0, 0.0}});
  pointCoordinates.push_back({{0.0, 0.0, 1.0}}); // Face 2
  pointCoordinates.push_back({{1.0, 0.0, 1.0}});
  pointCoordinates.push_back({{1.0, 1.0, 1.0}});
  pointCoordinates.push_back({{0.0, 1.0, 1.0}});

  // Create the points.
  vtkNew<vtkPoints> points;

  // Create a hexahedron from the points.
  vtkNew<vtkHexahedron> hex;

  for (auto i = 0; i < pointCoordinates.size(); ++i)
  {
    points->InsertNextPoint(pointCoordinates[i].data());
    hex->GetPointIds()->SetId(i, i);
  }

  // Add the hexahedron to a cell array.
  vtkNew<vtkCellArray> hexs;
  hexs->InsertNextCell(hex);

  // Add the points and hexahedron to an unstructured grid.
  vtkNew<vtkUnstructuredGrid> uGrid;
  uGrid->SetPoints(points);
  uGrid->InsertNextCell(hex->GetCellType(), hex->GetPointIds());

  // Visualize.
  vtkNew<vtkDataSetMapper> mapper;
  mapper->SetInputData(uGrid);

  vtkNew<vtkActor> actor;
  actor->GetProperty()->SetColor(colors->GetColor3d("PeachPuff").GetData());
  actor->SetMapper(mapper);

  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->SetWindowName("Hexahedron");
  renderWindow->AddRenderer(renderer);
  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);

  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("BkgColor").GetData());
  renderer->ResetCamera();
  renderer->GetActiveCamera()->Azimuth(30);
  renderer->GetActiveCamera()->Elevation(30);

  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(Hexahedron)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  CommonDataModel
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
  QUIET
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "Hexahedron: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(Hexahedron MACOSX_BUNDLE Hexahedron.cxx )
  target_link_libraries(Hexahedron PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS Hexahedron
  MODULES ${VTK_LIBRARIES}
)

cd Hexahedron/build

cmake ..

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

make

./Hexahedron