# BoundaryEdges

VTKExamples/Cxx/Meshes/BoundaryEdges

### Description

This filter will extract the boundary edges of a mesh. The original mesh is shown with the feature edges shown in red.

### Code

BoundaryEdges.cxx

    #include <vtkSmartPointer.h>
    #include <vtkFeatureEdges.h>
    #include <vtkPolyData.h>
    #include <vtkDiskSource.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkDiskSource> diskSource =
        vtkSmartPointer<vtkDiskSource>::New();
      diskSource->Update();

      vtkSmartPointer<vtkFeatureEdges> featureEdges =
        vtkSmartPointer<vtkFeatureEdges>::New();
      featureEdges->SetInputConnection(diskSource->GetOutputPort());
      featureEdges->BoundaryEdgesOn();
      featureEdges->FeatureEdgesOff();
      featureEdges->ManifoldEdgesOff();
      featureEdges->NonManifoldEdgesOff();
      featureEdges->Update();

      // Visualize
      vtkSmartPointer<vtkPolyDataMapper> edgeMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      edgeMapper->SetInputConnection(featureEdges->GetOutputPort());
      vtkSmartPointer<vtkActor> edgeActor =
        vtkSmartPointer<vtkActor>::New();
      edgeActor->SetMapper(edgeMapper);

      vtkSmartPointer<vtkPolyDataMapper> diskMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      diskMapper->SetInputConnection(diskSource->GetOutputPort());
      vtkSmartPointer<vtkActor> diskActor =
        vtkSmartPointer<vtkActor>::New();
      diskActor->SetMapper(diskMapper);

      // 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);

      renderer->AddActor(edgeActor);
      renderer->AddActor(diskActor);
      renderer->SetBackground(.3, .6, .3); // Background color green

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(BoundaryEdges)

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

    add_executable(BoundaryEdges MACOSX_BUNDLE BoundaryEdges.cxx )

    target_link_libraries(BoundaryEdges ${VTK_LIBRARIES})

### Download and Build BoundaryEdges

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

    cd BoundaryEdges/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:

    ./BoundaryEdges

WINDOWS USERS

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