# EllipticalCylinder

VTKExamples/Cxx/GeometricObjects/EllipticalCylinder

### Description

The example creates an elliptical cross-section and stores it in a vtkPolyData. Then, the vtkLinearExtrusionFilter creates an elliptical cylinderby extruding the vtkPolyLine along a vector. The example sets the backface property of the vtkActor to show the front and back face of the cylinder.

Seealso

See EllipticalCylinderDemo to see the vtkPolyLine and the vector represented as an oriented arrow.

### Code

EllipticalCylinder.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPolyLine.h>
    #include <vtkPoints.h>
    #include <vtkLinearExtrusionFilter.h>

    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkProperty.h>
    #include <vtkCamera.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleTrackballCamera.h>

    #include <vtkNamedColors.h>

    int main(int /* argc */, char * /* argv */ [])
    {

      double angle = 0;
      double r1, r2;
      double centerX, centerY;
      r1 = 50;
      r2 = 30;
      centerX = 10.0;
      centerY = 5.0;

      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      int id = 0;
      while (angle <= 2.0 * vtkMath::Pi() + (vtkMath::Pi() / 60.0))
      {
        points->InsertNextPoint(r1 * cos(angle) + centerX,
                                r2 * sin(angle) + centerY,
                                0.0);
        angle = angle + (vtkMath::Pi() / 60.0);
        ++id;
      }

      vtkSmartPointer<vtkPolyLine> line =
        vtkSmartPointer<vtkPolyLine>::New();
      line->GetPointIds()->SetNumberOfIds(id);
      for(unsigned int i = 0; i < static_cast<unsigned int>(id); ++i)
      {
        line->GetPointIds()->SetId(i,i);
      }

      vtkSmartPointer<vtkCellArray> lines =
        vtkSmartPointer<vtkCellArray>::New();
      lines->InsertNextCell(line);

      vtkSmartPointer<vtkPolyData> polyData =
        vtkSmartPointer<vtkPolyData>::New();
      polyData->SetPoints(points);
      polyData->SetLines(lines);

      vtkSmartPointer<vtkLinearExtrusionFilter> extrude =
        vtkSmartPointer<vtkLinearExtrusionFilter>::New();
      extrude->SetInputData(polyData);
      extrude->SetExtrusionTypeToNormalExtrusion();
      extrude->SetVector(0, 0, 100.0);
      extrude->Update();

      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      vtkSmartPointer<vtkPolyDataMapper> lineMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      lineMapper->SetInputData(polyData);

      vtkSmartPointer<vtkActor> lineActor =
        vtkSmartPointer<vtkActor>::New();
      lineActor->SetMapper(lineMapper);
      lineActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());

      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(extrude->GetOutputPort());

      vtkSmartPointer<vtkProperty> back =
        vtkSmartPointer<vtkProperty>::New();
      back->SetColor(colors->GetColor3d("Tomato").GetData());

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetColor(colors->GetColor3d("Banana").GetData());
      actor->SetBackfaceProperty(back);

      vtkSmartPointer<vtkRenderer> ren =
        vtkSmartPointer<vtkRenderer>::New();
      ren->SetBackground(colors->GetColor3d("Slate_grey").GetData());
      ren->AddActor(actor);
      ren->AddActor(lineActor);

      vtkSmartPointer<vtkRenderWindow> renWin =
        vtkSmartPointer<vtkRenderWindow>::New();
      renWin->AddRenderer(ren);
      renWin->SetSize(600, 600);

      vtkSmartPointer<vtkRenderWindowInteractor> iren =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      iren->SetRenderWindow(renWin);

      vtkSmartPointer<vtkInteractorStyleTrackballCamera> style =
        vtkSmartPointer<vtkInteractorStyleTrackballCamera>::New();
      iren->SetInteractorStyle(style);

      vtkSmartPointer<vtkCamera> camera =
        vtkSmartPointer<vtkCamera>::New();
      camera->SetPosition (0, 1, 0);
      camera->SetFocalPoint (0, 0, 0);
      camera->SetViewUp (0, 0, 1);
      camera->Azimuth(30);
      camera->Elevation(30);

      renWin->Render();

      ren->SetActiveCamera(camera);
      ren->ResetCamera();
      ren->ResetCameraClippingRange();
      iren->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(EllipticalCylinder)

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

    add_executable(EllipticalCylinder MACOSX_BUNDLE EllipticalCylinder.cxx )

    target_link_libraries(EllipticalCylinder ${VTK_LIBRARIES})

### Download and Build EllipticalCylinder

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

    cd EllipticalCylinder/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:

    ./EllipticalCylinder

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.