# GeometryFilter

VTKExamples/Cxx/PolyData/GeometryFilter

### Description

This example demonstrates how to convert an unstructured grid to a polydata. Currently nothing is done with the resulting polydata. If someone has a good data set that demonstrates the conversion, please let us know.

### Code

GeometryFilter.cxx

    #include <vtkVersion.h>
    #include <vtkSmartPointer.h>
    #include <vtkPolyData.h>
    #include <vtkUnstructuredGrid.h>
    #include <vtkCellArray.h>
    #include <vtkGeometryFilter.h>
    #include <vtkPointSource.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkUnstructuredGrid> unstructuredGrid =
        vtkSmartPointer<vtkUnstructuredGrid>::New();

      vtkSmartPointer<vtkGeometryFilter> geometryFilter =
        vtkSmartPointer<vtkGeometryFilter>::New();
    #if VTK_MAJOR_VERSION <= 5
      geometryFilter->SetInput(unstructuredGrid);
    #else
      geometryFilter->SetInputData(unstructuredGrid);
    #endif
      geometryFilter->Update();

      vtkPolyData* polydata = geometryFilter->GetOutput();

      std::cout << "Output has " << polydata->GetNumberOfPoints() << " points." << std::endl;

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(GeometryFilter)

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

    add_executable(GeometryFilter MACOSX_BUNDLE GeometryFilter.cxx)

    target_link_libraries(GeometryFilter ${VTK_LIBRARIES})

### Download and Build GeometryFilter

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

    cd GeometryFilter/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:

    ./GeometryFilter

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.