# 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.

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

Other languages

See (Python), (Java)

Question

### 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());

vtkNew<vtkRenderWindow> renWin;
renWin->SetWindowName("EllipticalCylinder");
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.")
target_link_libraries(EllipticalCylinder PRIVATE ${VTK_LIBRARIES} ) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS EllipticalCylinder MODULES${VTK_LIBRARIES}
)


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.