# ClipScalarVolume

VTKExamples/Cxx/ImageData/ClipScalarVolume

### Code

ClipScalarVolume.cxx

    #include <vtkSmartPointer.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>

    #include <vtkImplicitPolyDataDistance.h>
    #include <vtkSampleFunction.h>
    #include <vtkClipVolume.h>
    #include <vtkPolyDataNormals.h>
    #include <vtkImageData.h>

    #include <vtkActor.h>
    #include <vtkDataSetMapper.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkCamera.h>

    #include <vtkNamedColors.h>
    #include <array>
    #include <string>

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

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

      auto normals =
        vtkSmartPointer<vtkPolyDataNormals>::New();
      normals->SetInputData(polyData);
      normals->Update();

      // create a volume of distances to the input polydata
      auto implicitFunction =
        vtkSmartPointer<vtkImplicitPolyDataDistance>::New();
      implicitFunction->SetInput(normals->GetOutput());
      implicitFunction->SetInput(polyData);

      std::array<double, 6> bounds;
      polyData->GetBounds(bounds.data());
      std::array<double, 3> range;
      for (int i = 0; i < 3; ++i)
      {
        range[i] = bounds[2 * i + 1] - bounds[2 * i];
      }
      double maxRange = std::max(std::max(range[0], range[1]), range[2]);
      std::cout << "maxRange: " << maxRange << std::endl;

      auto sampleFunction =
        vtkSmartPointer<vtkSampleFunction>::New();
      sampleFunction->SetSampleDimensions(64, 64, 64);
      sampleFunction->SetSampleDimensions(128, 128, 128);
      sampleFunction->SetModelBounds(
        bounds[0] - .1 * maxRange, bounds[1] + .1 * maxRange,
        bounds[2] - .1 * maxRange, bounds[3] + .1 * maxRange,
        bounds[4] - .1 * maxRange, bounds[1] + .1 * maxRange);
      sampleFunction->SetImplicitFunction(implicitFunction);
      sampleFunction->Update();

      auto clipVolume =
        vtkSmartPointer<vtkClipVolume>::New();
      clipVolume->SetValue(maxRange * .01);
      clipVolume->SetInputData(sampleFunction->GetOutput());
      clipVolume->InsideOutOn();

      // Visualize
      auto colors =
        vtkSmartPointer<vtkNamedColors>::New();

      auto mapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      mapper->SetInputConnection(clipVolume->GetOutputPort());

      auto backProp =
        vtkSmartPointer<vtkProperty>::New();
      backProp->SetDiffuseColor(colors->GetColor3d("Banana").GetData());
      backProp->SetSpecular(.6);
      backProp->SetSpecularPower(30);

      auto actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->SetBackfaceProperty(backProp);
      actor->GetProperty()->SetDiffuseColor(colors->GetColor3d("Crimson").GetData());
      actor->GetProperty()->SetSpecular(.6);
      actor->GetProperty()->SetSpecularPower(30);

      auto renderer =
        vtkSmartPointer<vtkRenderer>::New();
      auto renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      auto renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      renderer->AddActor(actor);
      renderer->SetBackground(colors->GetColor3d("Silver").GetData());
      renderer->UseHiddenLineRemovalOn();

      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

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

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ClipScalarVolume)

    find_package(VTK COMPONENTS
      vtkCommonColor
      vtkCommonCore
      vtkCommonDataModel
      vtkFiltersCore
      vtkFiltersGeneral
      vtkFiltersSources
      vtkIOGeometry
      vtkIOLegacy
      vtkIOPLY
      vtkIOXML
      vtkImagingHybrid
      vtkInteractionStyle
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping ClipScalarVolume: ${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(ClipScalarVolume MACOSX_BUNDLE ClipScalarVolume.cxx )
      target_link_libraries(ClipScalarVolume PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(ClipScalarVolume MACOSX_BUNDLE ClipScalarVolume.cxx )
      target_link_libraries(ClipScalarVolume PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS ClipScalarVolume
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build ClipScalarVolume

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

    cd ClipScalarVolume/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:

    ./ClipScalarVolume

WINDOWS USERS

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