# MassProperties

VTKExamples/Cxx/Utilities/MassProperties

### Description

This example uses vtkMassProperties to compute the volume of a closed mesh. vtkmassProperties requires triangle with consistent ordering.

### Code

MassProperties.cxx

    #include <vtkSmartPointer.h>
    #include <vtkMassProperties.h>
    #include <vtkTriangleFilter.h>
    #include <vtkFillHolesFilter.h>
    #include <vtkCleanPolyData.h>
    #include <vtkPolyDataNormals.h>

    #include <vtkBYUReader.h>
    #include <vtkOBJReader.h>
    #include <vtkPLYReader.h>
    #include <vtkPolyDataReader.h>
    #include <vtkSTLReader.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkSphereSource.h>
    #include <vtksys/SystemTools.hxx>

    namespace
    {
    vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName);
    }

    int main (int argc, char *argv[])
    {
      vtkSmartPointer<vtkPolyData> polyData = ReadPolyData(argc > 1 ? argv[1] : "");;

      vtkSmartPointer<vtkCleanPolyData> cleanPolyDataFilter =
        vtkSmartPointer<vtkCleanPolyData>::New();
      cleanPolyDataFilter->SetInputData(polyData);

      vtkSmartPointer<vtkFillHolesFilter> fillHolesFilter =
        vtkSmartPointer<vtkFillHolesFilter>::New();
      fillHolesFilter->SetInputConnection(cleanPolyDataFilter->GetOutputPort());
      fillHolesFilter->SetHoleSize(1000.0);

      vtkSmartPointer<vtkTriangleFilter> triangleFilter =
        vtkSmartPointer<vtkTriangleFilter>::New();
      triangleFilter->SetInputConnection(fillHolesFilter->GetOutputPort());

      // Make the triangle windong order consistent
      vtkSmartPointer<vtkPolyDataNormals> normals =
        vtkSmartPointer<vtkPolyDataNormals>::New();
      normals->SetInputConnection(triangleFilter->GetOutputPort());
      normals->ConsistencyOn();
      normals->SplittingOff();

      vtkSmartPointer<vtkMassProperties> massProperties =
        vtkSmartPointer<vtkMassProperties>::New();
      massProperties->SetInputConnection(normals->GetOutputPort());
      massProperties->Update();
      massProperties->Print(std::cout);

      return EXIT_SUCCESS;
    }

    namespace
    {
    vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName)
    {
      vtkSmartPointer<vtkPolyData> polyData;
      std::string extension = vtksys::SystemTools::GetFilenameExtension(std::string(fileName));
      if (extension == ".ply")
      {
        vtkSmartPointer<vtkPLYReader> reader =
          vtkSmartPointer<vtkPLYReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".vtp")
      {
        vtkSmartPointer<vtkXMLPolyDataReader> reader =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".obj")
      {
        vtkSmartPointer<vtkOBJReader> reader =
          vtkSmartPointer<vtkOBJReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".stl")
      {
        vtkSmartPointer<vtkSTLReader> reader =
          vtkSmartPointer<vtkSTLReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".vtk")
      {
        vtkSmartPointer<vtkPolyDataReader> reader =
          vtkSmartPointer<vtkPolyDataReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".g")
      {
        vtkSmartPointer<vtkBYUReader> reader =
          vtkSmartPointer<vtkBYUReader>::New();
        reader->SetGeometryFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else
      {
        vtkSmartPointer<vtkSphereSource> source =
          vtkSmartPointer<vtkSphereSource>::New();
        source->SetPhiResolution(51);
        source->SetThetaResolution(51);
        source->Update();
        polyData = source->GetOutput();
      }
      return polyData;
    }
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(MassProperties)

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

    add_executable(MassProperties MACOSX_BUNDLE MassProperties.cxx )

    target_link_libraries(MassProperties ${VTK_LIBRARIES})

### Download and Build MassProperties

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

    cd MassProperties/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:

    ./MassProperties

WINDOWS USERS

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