# CombinePolyData

VTKExamples/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.

### Code

CombinePolyData.cxx

    #include <vtkVersion.h>
    #include <vtkSmartPointer.h>
    #include <vtkPolyData.h>
    #include <vtkSphereSource.h>
    #include <vtkConeSource.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkCleanPolyData.h>
    #include <vtkAppendPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int argc, char *argv[])
    {
      vtkSmartPointer<vtkPolyData> input1 =
        vtkSmartPointer<vtkPolyData>::New();
      vtkSmartPointer<vtkPolyData> input2 =
        vtkSmartPointer<vtkPolyData>::New();

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

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

        vtkSmartPointer<vtkConeSource> coneSource =
          vtkSmartPointer<vtkConeSource>::New();
        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];
        vtkSmartPointer<vtkXMLPolyDataReader> reader1 =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader1->SetFileName(inputFilename1.c_str());
        reader1->Update();
        input1->ShallowCopy(reader1->GetOutput());

        vtkSmartPointer<vtkXMLPolyDataReader> reader2 =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader2->SetFileName(inputFilename2.c_str());
        reader2->Update();
        input2->ShallowCopy(reader2->GetOutput());
      }

      //Append the two meshes
      vtkSmartPointer<vtkAppendPolyData> appendFilter =
        vtkSmartPointer<vtkAppendPolyData>::New();
    #if VTK_MAJOR_VERSION <= 5
      appendFilter->AddInputConnection(input1->GetProducerPort());
      appendFilter->AddInputConnection(input2->GetProducerPort());
    #else
      appendFilter->AddInputData(input1);
      appendFilter->AddInputData(input2);
    #endif
      appendFilter->Update();

      // Remove any duplicate points.
      vtkSmartPointer<vtkCleanPolyData> cleanFilter =
        vtkSmartPointer<vtkCleanPolyData>::New();
      cleanFilter->SetInputConnection(appendFilter->GetOutputPort());
      cleanFilter->Update();

      //Create a mapper and actor
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(cleanFilter->GetOutputPort());

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);

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

      //Add the actors to the scene
      renderer->AddActor(actor);
      renderer->SetBackground(.3, .2, .1); // Background color dark red

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(CombinePolyData)

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

    add_executable(CombinePolyData MACOSX_BUNDLE CombinePolyData.cxx )

    target_link_libraries(CombinePolyData ${VTK_LIBRARIES})

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