Skip to content

CombinePolyData

vtk-examples/Cxx/Filtering/CombinePolyData

Description

This example reads two .vtp files (or produces them if not specified as command line arguments), combines them, and displays the result to the screen.

Other languages

See (Python)

Question

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

Code

CombinePolyData.cxx

#include <vtkActor.h>
#include <vtkAppendPolyData.h>
#include <vtkCamera.h>
#include <vtkCleanPolyData.h>
#include <vtkConeSource.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>
#include <vtkXMLPolyDataReader.h>

int main(int argc, char* argv[])
{
  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkPolyData> input1;
  vtkNew<vtkPolyData> input2;

  if (argc == 1) // command line arguments not specified
  {
    vtkNew<vtkSphereSource> sphereSource;
    sphereSource->SetCenter(5, 0, 0);
    sphereSource->Update();

    input1->ShallowCopy(sphereSource->GetOutput());

    vtkNew<vtkConeSource> coneSource;
    coneSource->Update();

    input2->ShallowCopy(coneSource->GetOutput());
  }
  else
  {
    if (argc != 3)
    {
      std::cout << "argc = " << argc << std::endl;
      std::cout << "Required arguments: File1 File2" << std::endl;
      return EXIT_FAILURE;
    }
    std::string inputFilename1 = argv[1];
    std::string inputFilename2 = argv[2];
    vtkNew<vtkXMLPolyDataReader> reader1;
    reader1->SetFileName(inputFilename1.c_str());
    reader1->Update();
    input1->ShallowCopy(reader1->GetOutput());

    vtkNew<vtkXMLPolyDataReader> reader2;
    reader2->SetFileName(inputFilename2.c_str());
    reader2->Update();
    input2->ShallowCopy(reader2->GetOutput());
  }

  // Append the two meshes
  vtkNew<vtkAppendPolyData> appendFilter;
  appendFilter->AddInputData(input1);
  appendFilter->AddInputData(input2);

  // Remove any duplicate points.
  vtkNew<vtkCleanPolyData> cleanFilter;
  cleanFilter->SetInputConnection(appendFilter->GetOutputPort());
  cleanFilter->Update();

  // Create a mapper and actor
  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(cleanFilter->GetOutputPort());

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);

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

  // Add the actors to the scene
  renderer->AddActor(actor);

  // Render and interact
  renderWindowInteractor->Initialize();
  renderWindow->Render();
  renderer->SetBackground(colors->GetColor3d("deep_ochre").GetData());
  renderer->GetActiveCamera()->Zoom(0.9);
  renderWindow->SetWindowName("CombinePolyData");
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(CombinePolyData)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersCore
  vtkFiltersSources
  vtkIOXML
  vtkInteractionStyle
  vtkRenderingContextOpenGL2
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingGL2PSOpenGL2
  vtkRenderingOpenGL2
  QUIET
)

if (NOT VTK_FOUND)
  message("Skipping CombinePolyData: ${VTK_NOT_FOUND_MESSAGE}")
  return()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(CombinePolyData MACOSX_BUNDLE CombinePolyData.cxx )
  target_link_libraries(CombinePolyData PRIVATE ${VTK_LIBRARIES})
else()
  # 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(CombinePolyData MACOSX_BUNDLE CombinePolyData.cxx )
  target_link_libraries(CombinePolyData PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS CombinePolyData
    MODULES ${VTK_LIBRARIES}
    )
endif()

Download and Build CombinePolyData

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

cd CombinePolyData/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:

./CombinePolyData

WINDOWS USERS

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