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EllipticalCylinder

vtk-examples/Cxx/GeometricObjects/EllipticalCylinder


Description

The example creates an elliptical cross-section and stores it in a vtkPolyData. Then, the vtkLinearExtrusionFilter creates an elliptical cylinder by 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.

See also

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

Other languages

See (Python), (Java)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code

EllipticalCylinder.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkLinearExtrusionFilter.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyDataMapper.h>
#include <vtkPolyLine.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.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;

  vtkNew<vtkPoints> points;
  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;
  }

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

  vtkNew<vtkCellArray> lines;
  lines->InsertNextCell(line);

  vtkNew<vtkPolyData> polyData;
  polyData->SetPoints(points);
  polyData->SetLines(lines);

  vtkNew<vtkLinearExtrusionFilter> extrude;
  extrude->SetInputData(polyData);
  extrude->SetExtrusionTypeToNormalExtrusion();
  extrude->SetVector(0, 0, 100.0);
  extrude->Update();

  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkPolyDataMapper> lineMapper;
  lineMapper->SetInputData(polyData);

  vtkNew<vtkActor> lineActor;
  lineActor->SetMapper(lineMapper);
  lineActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());

  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(extrude->GetOutputPort());

  vtkNew<vtkProperty> back;
  back->SetColor(colors->GetColor3d("Tomato").GetData());

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

  vtkNew<vtkRenderer> ren;
  ren->SetBackground(colors->GetColor3d("SlateGray").GetData());
  ren->AddActor(actor);
  ren->AddActor(lineActor);

  vtkNew<vtkRenderWindow> renWin;
  renWin->SetWindowName("EllipticalCylinder");
  renWin->AddRenderer(ren);
  renWin->SetSize(600, 600);

  vtkNew<vtkRenderWindowInteractor> iren;
  iren->SetRenderWindow(renWin);

  vtkNew<vtkInteractorStyleTrackballCamera> style;
  iren->SetInteractorStyle(style);

  vtkNew<vtkCamera> camera;
  camera->SetPosition(0, 1, 0);
  camera->SetFocalPoint(0, 0, 0);
  camera->SetViewUp(0, 0, 1);
  camera->Azimuth(30);
  camera->Elevation(30);

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

  renWin->Render();
  iren->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(EllipticalCylinder)

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

if (NOT VTK_FOUND)
  message(FATAL_ERROR "EllipticalCylinder: 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(EllipticalCylinder MACOSX_BUNDLE EllipticalCylinder.cxx )
  target_link_libraries(EllipticalCylinder PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS EllipticalCylinder
  MODULES ${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

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