# SurfaceFromUnorganizedPoints

VTKExamples/Cxx/Filtering/SurfaceFromUnorganizedPoints

### Description

This example creates points on a sphere and then finds the surface through the points. If an optional polydata file is provided, the example operates on the points in that polydata.

### Code

SurfaceFromUnorganizedPoints.cxx

    #include <vtkVersion.h>
    #include <vtkSmartPointer.h>

    #include <vtkSurfaceReconstructionFilter.h>
    #include <vtkProgrammableSource.h>
    #include <vtkContourFilter.h>
    #include <vtkReverseSense.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkPolyData.h>
    #include <vtkCamera.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSphereSource.h>
    #include <vtkXMLPolyDataReader.h>

    int main(int argc, char *argv[])
    {

      vtkSmartPointer<vtkPolyData> input;
      if(argc > 1)
      {
        vtkSmartPointer<vtkXMLPolyDataReader> reader =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName(argv[1]);
        reader->Update();
        input = reader->GetOutput();
      }
      else
      {
        vtkSmartPointer<vtkSphereSource> sphereSource =
          vtkSmartPointer<vtkSphereSource>::New();
        sphereSource->Update();
        input = sphereSource->GetOutput();
      }

      vtkSmartPointer<vtkPolyData> polydata =
        vtkSmartPointer<vtkPolyData>::New();
      polydata->SetPoints(input->GetPoints());

      // Construct the surface and create isosurface.
      vtkSmartPointer<vtkSurfaceReconstructionFilter> surf =
        vtkSmartPointer<vtkSurfaceReconstructionFilter>::New();
    #if VTK_MAJOR_VERSION <= 5
      surf->SetInput(polydata);
    #else
      surf->SetInputData(polydata);
    #endif

      vtkSmartPointer<vtkContourFilter> cf =
        vtkSmartPointer<vtkContourFilter>::New();
      cf->SetInputConnection(surf->GetOutputPort());
      cf->SetValue(0, 0.0);

      // Sometimes the contouring algorithm can create a volume whose gradient
      // vector and ordering of polygon (using the right hand rule) are
      // inconsistent. vtkReverseSense cures this problem.
      vtkSmartPointer<vtkReverseSense> reverse =
        vtkSmartPointer<vtkReverseSense>::New();
      reverse->SetInputConnection(cf->GetOutputPort());
      reverse->ReverseCellsOn();
      reverse->ReverseNormalsOn();

      vtkSmartPointer<vtkPolyDataMapper> map =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      map->SetInputConnection(reverse->GetOutputPort());
      map->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> surfaceActor =
        vtkSmartPointer<vtkActor>::New();
      surfaceActor->SetMapper(map);

      // Create the RenderWindow, Renderer and both Actors
      vtkSmartPointer<vtkRenderer> ren =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renWin =
        vtkSmartPointer<vtkRenderWindow>::New();
      renWin->AddRenderer(ren);
      vtkSmartPointer<vtkRenderWindowInteractor> iren =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      iren->SetRenderWindow(renWin);

      // Add the actors to the renderer, set the background and size
      ren->AddActor(surfaceActor);
      ren->SetBackground(.2, .3, .4);

      renWin->Render();
      iren->Start();

      return EXIT_SUCCESS;

    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(SurfaceFromUnorganizedPoints)

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

    add_executable(SurfaceFromUnorganizedPoints MACOSX_BUNDLE SurfaceFromUnorganizedPoints.cxx )

    target_link_libraries(SurfaceFromUnorganizedPoints ${VTK_LIBRARIES})

### Download and Build SurfaceFromUnorganizedPoints

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

    cd SurfaceFromUnorganizedPoints/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:

    ./SurfaceFromUnorganizedPoints

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.