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# PolyDataGetPoint

VTKEx/Cxx/PolyData/PolyDataGetPoint

### Description

This example demonstrates how to obtain the coordinates of a point in a vtkPolyData object.

- Suggested by Sara Rolfe

Other languages

See (CSharp)

Question

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### Code

PolyDataGetPoint.cxx

    #include <vtkSphereSource.h>
    #include <vtkSmartPointer.h>
    #include <vtkPolyData.h>

    int main(int, char*[])
    {
      // Create a sphere
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->Update();

      vtkPolyData* polydata = sphereSource->GetOutput();

      // Write all of the coordinates of the points in the vtkPolyData to the console.
      for(vtkIdType i = 0; i < polydata->GetNumberOfPoints(); i++)
      {
        double p[3];
        polydata->GetPoint(i,p);
        // This is identical to:
        // polydata->GetPoints()->GetPoint(i,p);
        std::cout << "Point " << i << " : (" << p[0] << " " << p[1] << " " << p[2] << ")" << std::endl;
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(PolyDataGetPoint)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkFiltersSources QUIET)
    if (NOT VTK_FOUND)
      message("Skipping PolyDataGetPoint: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(PolyDataGetPoint MACOSX_BUNDLE PolyDataGetPoint.cxx )
      target_link_libraries(PolyDataGetPoint PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(PolyDataGetPoint MACOSX_BUNDLE PolyDataGetPoint.cxx )
      target_link_libraries(PolyDataGetPoint PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS PolyDataGetPoint
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build PolyDataGetPoint

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

    cd PolyDataGetPoint/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:

    ./PolyDataGetPoint

WINDOWS USERS

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