# Tetrahedron

VTKExamples/Cxx/GeometricObjects/Tetrahedron

### Description

Tetrahedron. The tetrahedron is a primary three-dimensional cell. The tetrahedron is defined by a list of four nonplanar points. The tetrahedron has six edges and four triangular faces.

### Code

Tetrahedron.cxx

    #include <vtkVersion.h>
    #include <vtkSmartPointer.h>
    #include <vtkCellArray.h>
    #include <vtkTetra.h>
    #include <vtkUnstructuredGrid.h>
    #include <vtkPoints.h>
    #include <vtkCellType.h>
    #include <vtkDataSetMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int, char*[])
    {
      vtkSmartPointer< vtkPoints > points =
        vtkSmartPointer< vtkPoints > :: New();
      points->InsertNextPoint(0, 0, 0);
      points->InsertNextPoint(1, 0, 0);
      points->InsertNextPoint(1, 1, 0);
      points->InsertNextPoint(0, 1, 1);
      points->InsertNextPoint(5, 5, 5);
      points->InsertNextPoint(6, 5, 5);
      points->InsertNextPoint(6, 6, 5);
      points->InsertNextPoint(5, 6, 6);

      // Method 1
      vtkSmartPointer<vtkUnstructuredGrid> unstructuredGrid1 =
        vtkSmartPointer<vtkUnstructuredGrid>::New();
      unstructuredGrid1->SetPoints(points);

      vtkIdType ptIds[] = {0, 1, 2, 3};
      unstructuredGrid1->InsertNextCell( VTK_TETRA, 4, ptIds );

      // Method 2
      vtkSmartPointer<vtkUnstructuredGrid> unstructuredGrid2 =
        vtkSmartPointer<vtkUnstructuredGrid>::New();
      unstructuredGrid2->SetPoints(points);

      vtkSmartPointer<vtkTetra> tetra =
        vtkSmartPointer<vtkTetra>::New();

      tetra->GetPointIds()->SetId(0, 4);
      tetra->GetPointIds()->SetId(1, 5);
      tetra->GetPointIds()->SetId(2, 6);
      tetra->GetPointIds()->SetId(3, 7);

      vtkSmartPointer<vtkCellArray> cellArray =
        vtkSmartPointer<vtkCellArray>::New();
      cellArray->InsertNextCell(tetra);
      unstructuredGrid2->SetCells(VTK_TETRA, cellArray);

      // Create a mapper and actor
      vtkSmartPointer<vtkDataSetMapper> mapper1 =
        vtkSmartPointer<vtkDataSetMapper>::New();
    #if VTK_MAJOR_VERSION <= 5
      mapper1->SetInputConnection(unstructuredGrid1->GetProducerPort());
    #else
      mapper1->SetInputData(unstructuredGrid1);
    #endif

      vtkSmartPointer<vtkActor> actor1 =
        vtkSmartPointer<vtkActor>::New();
      actor1->SetMapper(mapper1);

      // Create a mapper and actor
      vtkSmartPointer<vtkDataSetMapper> mapper2 =
        vtkSmartPointer<vtkDataSetMapper>::New();
    #if VTK_MAJOR_VERSION <= 5
      mapper2->SetInputConnection(unstructuredGrid2->GetProducerPort());
    #else
      mapper2->SetInputData(unstructuredGrid2);
    #endif

      vtkSmartPointer<vtkActor> actor2 =
        vtkSmartPointer<vtkActor>::New();
      actor2->SetMapper(mapper2);

      // Create a renderer, render window, and interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      // Add the actor to the scene
      renderer->AddActor(actor1);
      renderer->AddActor(actor2);
      renderer->SetBackground(.3, .6, .3); // Background color green

      // Render and interact
      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(Tetrahedron)

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

    add_executable(Tetrahedron MACOSX_BUNDLE Tetrahedron.cxx )

    target_link_libraries(Tetrahedron ${VTK_LIBRARIES})

### Download and Build Tetrahedron

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

    cd Tetrahedron/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:

    ./Tetrahedron

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.