Skip to content

TubeFilter

vtk-examples/Cxx/PolyData/TubeFilter


Description

This example creates a tube around a line. This is helpful because when you zoom the camera, the thickness of a line remains constant, while the thickness of a tube varies.

Other languages

See (Python), (Java)

Question

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

Code

TubeFilter.cxx

#include <vtkActor.h>
#include <vtkLineSource.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkTubeFilter.h>

/*
 * This example creates a tube around a line.
 * This is helpful because when you zoom the camera,
 * the thickness of a line remains constant,
 * while the thickness of a tube varies.
 * */

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;
  // Create a line.
  vtkNew<vtkLineSource> lineSource;
  lineSource->SetPoint1(1.0, 0.0, 0.0);
  lineSource->SetPoint2(0.0, 1.0, 0.0);

  // Create a mapper and actor.
  vtkNew<vtkPolyDataMapper> lineMapper;
  lineMapper->SetInputConnection(lineSource->GetOutputPort());
  vtkNew<vtkActor> lineActor;
  lineActor->GetProperty()->SetColor(colors->GetColor3d("Red").GetData());
  lineActor->SetMapper(lineMapper);

  // Create a tube (cylinder) around the line.
  vtkNew<vtkTubeFilter> tubeFilter;
  tubeFilter->SetInputConnection(lineSource->GetOutputPort());
  tubeFilter->SetRadius(.025); // default is .5
  tubeFilter->SetNumberOfSides(50);
  tubeFilter->Update();

  // Create a mapper and actor.
  vtkNew<vtkPolyDataMapper> tubeMapper;
  tubeMapper->SetInputConnection(tubeFilter->GetOutputPort());
  vtkNew<vtkActor> tubeActor;
  tubeActor->GetProperty()->SetOpacity(
      0.5); // Make the tube have some transparency.
  tubeActor->SetMapper(tubeMapper);

  // Create a renderer, render window, and interactor.
  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("TubeFilter");

  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);

  // Add the actor to the scene.
  renderer->AddActor(tubeActor);
  renderer->AddActor(lineActor);
  renderer->SetBackground(colors->GetColor3d("DarkSlateGray").GetData());

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

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(TubeFilter)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  FiltersCore
  FiltersSources
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

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

Download and Build TubeFilter

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

cd TubeFilter/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:

./TubeFilter

WINDOWS USERS

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