# Polyhedron

VTKExamples/Cxx/GeometricObjects/Polyhedron

### Code

Polyhedron.cxx

    #include <vtkSmartPointer.h>

    #include <vtkVersion.h>
    #include <vtkUnstructuredGrid.h>
    #include <vtkPolyhedron.h>
    #include <vtkCellArray.h>
    #include <vtkPointData.h>
    #include <vtkCellData.h>
    #include <vtkIdList.h>
    #include <vtkPoints.h>
    #include <vtkDataArray.h>
    #include <vtkXMLUnstructuredGridWriter.h>

    int main( int, char*[] )
    {
      // create polyhedron (cube)
      vtkIdType pointIds[8] = {0, 1, 2, 3, 4, 5, 6, 7};

      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint(-1.0,-1.0,-1.0);
      points->InsertNextPoint( 1.0,-1.0,-1.0);
      points->InsertNextPoint( 1.0, 1.0,-1.0);
      points->InsertNextPoint(-1.0, 1.0,-1.0);
      points->InsertNextPoint(-1.0,-1.0, 1.0);
      points->InsertNextPoint( 1.0,-1.0, 1.0);
      points->InsertNextPoint( 1.0, 1.0, 1.0);
      points->InsertNextPoint(-1.0, 1.0, 1.0);

      vtkSmartPointer<vtkCellArray> faces =
        vtkSmartPointer<vtkCellArray>::New();
      vtkIdType face0[4] = {0, 3, 2, 1};
      vtkIdType face1[4] = {0, 4, 7, 3};
      vtkIdType face2[4] = {4, 5, 6, 7};
      vtkIdType face3[4] = {5, 1, 2, 6};
      vtkIdType face4[4] = {0, 1, 5, 4};
      vtkIdType face5[4] = {2, 3, 7, 6};

      faces->InsertNextCell(4, face0);
      faces->InsertNextCell(4, face1);
      faces->InsertNextCell(4, face2);
      faces->InsertNextCell(4, face3);
      faces->InsertNextCell(4, face4);
      faces->InsertNextCell(4, face5);

      vtkSmartPointer<vtkUnstructuredGrid> ugrid =
        vtkSmartPointer<vtkUnstructuredGrid>::New();
      ugrid->SetPoints(points);
      ugrid->InsertNextCell(
        VTK_POLYHEDRON, 8, pointIds,
        6, faces->GetPointer());

      vtkSmartPointer<vtkXMLUnstructuredGridWriter> writer =
        vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
    #if VTK_MAJOR_VERSION <= 5
      writer->SetInput(ugrid);
    #else
      writer->SetInputData(ugrid);
    #endif
      writer->SetFileName("polyhedron.vtu");
      writer->SetDataModeToAscii();
      writer->Update();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(Polyhedron)

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

    add_executable(Polyhedron MACOSX_BUNDLE Polyhedron.cxx )

    target_link_libraries(Polyhedron ${VTK_LIBRARIES})

### Download and Build Polyhedron

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

    cd Polyhedron/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:

    ./Polyhedron

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