# BooleanOperationPolyDataFilter

VTKExamples/Cxx/PolyData/BooleanOperationPolyDataFilter

### Description

The vtkBooleanOperationPolyDataFilter works best with "clean" data, so this examples first runs vtkTriangleFilter and then vtkCleanPolyData.

This example can be run in three ways:

1. BooleanOperationPolyDataFilter - Computes the intersection of two spheres

2. BooleanOperationPolyDataFilter intersection|difference|union - Computes the intersection(difference or union) of two spheres

3. BooleanOperationPolyDataFilter input1.vtk intersection|difference|union input2.vtk - Computes the intersection(difference or union) of two vtkPolyData's

Cite

See Boolean Operations on Surfaces in VTK Without External Libraries for details on the algorithm.

Seealso

LoopBooleanPolyDataFilter uses an alternative algorithm to do the boolean operations.

### Code

BooleanOperationPolyDataFilter.cxx

    #include <vtkSmartPointer.h>
    #include <vtkBooleanOperationPolyDataFilter.h>

    #include <vtkCleanPolyData.h>
    #include <vtkTriangleFilter.h>
    #include <vtkActor.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkNamedColors.h>

    #include <vtkBYUReader.h>
    #include <vtkOBJReader.h>
    #include <vtkPLYReader.h>
    #include <vtkPolyDataReader.h>
    #include <vtkSTLReader.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkSphereSource.h>
    #include <vtksys/SystemTools.hxx>

    #include <vtkCamera.h>
    namespace
    {
    vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName);
    void PositionCamera(vtkSmartPointer<vtkRenderer> &renderer,
                        double *viewUp,
                        double *position);
    }

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

      std::string operation("intersection");

      if (argc == 4)
      {
        vtkSmartPointer<vtkPolyData> poly1;
        poly1 = ReadPolyData(argv[1]);
        vtkSmartPointer<vtkTriangleFilter> tri1 =
          vtkSmartPointer<vtkTriangleFilter>::New();
        tri1->SetInputData(poly1);
        vtkSmartPointer<vtkCleanPolyData> clean1 =
          vtkSmartPointer<vtkCleanPolyData>::New();
        clean1->SetInputConnection(tri1->GetOutputPort());
        clean1->Update();
        input1 = clean1->GetOutput();

        vtkSmartPointer<vtkPolyData> poly2;
        poly2 = ReadPolyData(argv[3]);
        vtkSmartPointer<vtkTriangleFilter> tri2 =
          vtkSmartPointer<vtkTriangleFilter>::New();
        tri2->SetInputData(poly2);
        tri2->Update();
        vtkSmartPointer<vtkCleanPolyData> clean2 =
          vtkSmartPointer<vtkCleanPolyData>::New();
        clean2->SetInputConnection(tri2->GetOutputPort());
        clean2->Update();
        input2 = clean2->GetOutput();
        operation = argv[2];
      }
      else
      {
        vtkSmartPointer<vtkSphereSource> sphereSource1 =
          vtkSmartPointer<vtkSphereSource>::New();
        sphereSource1->SetCenter(.25, 0, 0);
        sphereSource1->SetPhiResolution(21);
        sphereSource1->SetThetaResolution(21);
        sphereSource1->Update();
        input1 = sphereSource1->GetOutput();

        vtkSmartPointer<vtkSphereSource> sphereSource2 =
          vtkSmartPointer<vtkSphereSource>::New();
        sphereSource2->Update();
        input2 = sphereSource2->GetOutput();

        if (argc == 2)
        {
          operation = argv[1];
        }
      }

      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      vtkSmartPointer<vtkPolyDataMapper> input1Mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      input1Mapper->SetInputData( input1 );
      input1Mapper->ScalarVisibilityOff();
      vtkSmartPointer<vtkActor> input1Actor =
        vtkSmartPointer<vtkActor>::New();
      input1Actor->SetMapper( input1Mapper );
      input1Actor->GetProperty()->SetDiffuseColor(colors->GetColor3d("Tomato").GetData());
      input1Actor->GetProperty()->SetSpecular(.6);
      input1Actor->GetProperty()->SetSpecularPower(20);
      input1Actor->SetPosition(
        input1->GetBounds()[1]-input1->GetBounds()[0],
        0, 0);
      vtkSmartPointer<vtkPolyDataMapper> input2Mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      input2Mapper->SetInputData( input2 );
      input2Mapper->ScalarVisibilityOff();
      vtkSmartPointer<vtkActor> input2Actor =
        vtkSmartPointer<vtkActor>::New();
      input2Actor->SetMapper( input2Mapper );
      input2Actor->GetProperty()->SetDiffuseColor(colors->GetColor3d("Mint").GetData());
      input2Actor->GetProperty()->SetSpecular(.6);
      input2Actor->GetProperty()->SetSpecularPower(20);
      input2Actor->SetPosition(
        -(input1->GetBounds()[1]-input1->GetBounds()[0]),
        0, 0);
      vtkSmartPointer<vtkBooleanOperationPolyDataFilter> booleanOperation =
        vtkSmartPointer<vtkBooleanOperationPolyDataFilter>::New();
      if (operation == "union")
      {
          booleanOperation->SetOperationToUnion();
      }
      else if (operation == "intersection")
      {
          booleanOperation->SetOperationToIntersection();
      }
      else if (operation == "difference")
      {
          booleanOperation->SetOperationToDifference();
      }
      else
      {
        std::cout << "Unknown operation: " << operation << std::endl;
        return EXIT_FAILURE;
      }
      booleanOperation->SetInputData( 0, input1 );
      booleanOperation->SetInputData( 1, input2 );

      vtkSmartPointer<vtkPolyDataMapper> booleanOperationMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      booleanOperationMapper->SetInputConnection( booleanOperation->GetOutputPort() );
      booleanOperationMapper->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> booleanOperationActor =
        vtkSmartPointer<vtkActor>::New();
      booleanOperationActor->SetMapper( booleanOperationMapper );
      booleanOperationActor->GetProperty()->SetDiffuseColor(colors->GetColor3d("Banana").GetData());
      booleanOperationActor->GetProperty()->SetSpecular(.6);
      booleanOperationActor->GetProperty()->SetSpecularPower(20);

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddViewProp(input1Actor);
      renderer->AddViewProp(input2Actor);
      renderer->AddViewProp(booleanOperationActor);
      renderer->SetBackground(colors->GetColor3d("Silver").GetData());
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer( renderer );
      renderWindow->SetSize(640, 480);
      double viewUp[3] = {0.0, 0.0, 1.0};
      double position[3] = {0.0, -1.0, 0.0};
      PositionCamera(renderer, viewUp, position);
      renderer->GetActiveCamera()->Dolly(1.5);
      renderer->ResetCameraClippingRange();

      vtkSmartPointer<vtkRenderWindowInteractor> renWinInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renWinInteractor->SetRenderWindow( renderWindow );

      renderWindow->Render();
      renWinInteractor->Start();

      return EXIT_SUCCESS;
    }
    namespace
    {
    vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName)
    {
      vtkSmartPointer<vtkPolyData> polyData;
      std::string extension = vtksys::SystemTools::GetFilenameExtension(std::string(fileName));
      if (extension == ".ply")
      {
        vtkSmartPointer<vtkPLYReader> reader =
          vtkSmartPointer<vtkPLYReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".vtp")
      {
        vtkSmartPointer<vtkXMLPolyDataReader> reader =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".obj")
      {
        vtkSmartPointer<vtkOBJReader> reader =
          vtkSmartPointer<vtkOBJReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".stl")
      {
        vtkSmartPointer<vtkSTLReader> reader =
          vtkSmartPointer<vtkSTLReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".vtk")
      {
        vtkSmartPointer<vtkPolyDataReader> reader =
          vtkSmartPointer<vtkPolyDataReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".g")
      {
        vtkSmartPointer<vtkBYUReader> reader =
          vtkSmartPointer<vtkBYUReader>::New();
        reader->SetGeometryFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else
      {
        vtkSmartPointer<vtkSphereSource> source =
          vtkSmartPointer<vtkSphereSource>::New();
        source->Update();
        polyData = source->GetOutput();
      }
      return polyData;
    }

    void PositionCamera(vtkSmartPointer<vtkRenderer> &renderer,
                        double *viewUp,
                        double *position)
    {
      renderer->GetActiveCamera()->SetFocalPoint(0.0, 0.0, 0.0);
      renderer->GetActiveCamera()->SetViewUp(viewUp);
      renderer->GetActiveCamera()->SetPosition(position);
      renderer->ResetCamera();
      return;
    }
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(BooleanOperationPolyDataFilter)

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

    add_executable(BooleanOperationPolyDataFilter MACOSX_BUNDLE BooleanOperationPolyDataFilter.cxx )

    target_link_libraries(BooleanOperationPolyDataFilter ${VTK_LIBRARIES})

### Download and Build BooleanOperationPolyDataFilter

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

    cd BooleanOperationPolyDataFilter/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:

    ./BooleanOperationPolyDataFilter

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.