MassProperties

Description¶

This example uses vtkMassProperties to compute the volume of a closed mesh. vtkMassProperties requires triangles with consistent ordering. This example uses vtkFillHolesFilter and vtkTriangleFilter to ensure a closed, triangulated mesh. vtkPolyDataNormals enforces consistent normals.

If run with no arguments, a vtkSphereSource generates the vtkPolyData. Or given a file containing vtkPolyData, it computes that data's volume and surface area.

Cite

Alyassin A.M. et al, "Evaluation of new algorithms for the interactive measurement of surface area and volume", Med Phys 21(6) 1994.

Other languages

See (PythonicAPI)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code¶

MassProperties.cxx

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

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

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

int main(int argc, char* argv[])
{
  // For example, try Torso.vtp, if the file is not found a sphere is used.
  vtkSmartPointer<vtkPolyData> polyData = ReadPolyData(argc > 1 ? argv[1] : "");

  vtkNew<vtkFillHolesFilter> fillHolesFilter;
  fillHolesFilter->SetInputData(polyData);
  fillHolesFilter->SetHoleSize(1000.0);

  vtkNew<vtkTriangleFilter> triangleFilter;
  triangleFilter->SetInputConnection(fillHolesFilter->GetOutputPort());

  // Make the triangle winding order consistent.
  vtkNew<vtkPolyDataNormals> normals;
  normals->SetInputConnection(triangleFilter->GetOutputPort());
  normals->ConsistencyOn();
  normals->SplittingOff();

  vtkNew<vtkMassProperties> massProperties;
  massProperties->SetInputConnection(normals->GetOutputPort());
  massProperties->Update();
  std::cout << "Volume: " << massProperties->GetVolume() << std::endl
            << "    VolumeX: " << massProperties->GetVolumeX() << std::endl
            << "    VolumeY: " << massProperties->GetVolumeY() << std::endl
            << "    VolumeZ: " << massProperties->GetVolumeZ() << std::endl
            << "Area:   " << massProperties->GetSurfaceArea() << std::endl
            << "    MinCellArea: " << massProperties->GetMinCellArea()
            << std::endl
            << "    MaxCellArea: " << massProperties->GetMaxCellArea()
            << std::endl
            << "NormalizedShapeIndex: "
            << massProperties->GetNormalizedShapeIndex() << std::endl;

  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")
  {
    vtkNew<vtkPLYReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".vtp")
  {
    vtkNew<vtkXMLPolyDataReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".obj")
  {
    vtkNew<vtkOBJReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".stl")
  {
    vtkNew<vtkSTLReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".vtk")
  {
    vtkNew<vtkPolyDataReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".g")
  {
    vtkNew<vtkBYUReader> reader;
    reader->SetGeometryFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else
  {
    vtkNew<vtkSphereSource> source;
    source->SetPhiResolution(51);
    source->SetThetaResolution(51);
    source->Update();
    polyData = source->GetOutput();
  }
  return polyData;
}
} // namespace

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(MassProperties)

find_package(VTK COMPONENTS 
  CommonCore
  FiltersCore
  FiltersModeling
  FiltersSources
  IOGeometry
  IOLegacy
  IOPLY
  IOXML
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "MassProperties: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(MassProperties MACOSX_BUNDLE MassProperties.cxx )
  target_link_libraries(MassProperties PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS MassProperties
  MODULES ${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.