# WriteSTL

VTKExamples/Cxx/IO/WriteSTL

### Description

An [(file format)|STL file]]([wikipedia:STL) describes a triangulated three-dimensional surface by the unit normal and vertices (ordered by the right-hand rule) of the triangles. This example saves a 3D geometric data stored in a {{class vtkPolyData}} to an STL file using {{class vtkSTLWriter}}.

### Code

WriteSTL.cxx

    #include <vtkPolyData.h>
    #include <vtkSTLWriter.h>
    #include <vtkSTLReader.h>
    #include <vtkSphereSource.h>
    #include <vtkSmartPointer.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int argc, char *argv[])
    {
      if(argc != 2)
      {
        std::cout << "Required parameters: filename.stl" << std::endl;
        return EXIT_FAILURE;
      }

      std::string filename = argv[1];

      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->Update();

      vtkSmartPointer<vtkSTLWriter> stlWriter =
        vtkSmartPointer<vtkSTLWriter>::New();
      stlWriter->SetFileName(filename.c_str());
      stlWriter->SetInputConnection(sphereSource->GetOutputPort());
      stlWriter->Write();

      // Read and display for verification
      vtkSmartPointer<vtkSTLReader> reader =
        vtkSmartPointer<vtkSTLReader>::New();
      reader->SetFileName(filename.c_str());
      reader->Update();

      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(sphereSource->GetOutputPort());

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

      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(actor);
      renderer->SetBackground(.3, .6, .3); // Background color green

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(WriteSTL)

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

    add_executable(WriteSTL MACOSX_BUNDLE WriteSTL.cxx )

    target_link_libraries(WriteSTL ${VTK_LIBRARIES})

### Download and Build WriteSTL

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

    cd WriteSTL/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:

    ./WriteSTL

WINDOWS USERS

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