Skip to content

GenericClip

vtk-examples/Cxx/Filtering/GenericClip


Description

Warning

This example requires vtk 6.0 or greater.

Question

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

Code

GenericClip.cxx

#include <vtkActor.h>
#include <vtkBridgeDataSet.h> // Must build VTK with BUILD_TESTING=ON
#include <vtkCellData.h>
#include <vtkContourFilter.h>
#include <vtkDataSetMapper.h>
#include <vtkDelaunay3D.h>
#include <vtkElevationFilter.h>
#include <vtkGenericClip.h>
#include <vtkIdFilter.h>
#include <vtkIdTypeArray.h>
#include <vtkImageData.h>
#include <vtkImplicitDataSet.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPlane.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSampleFunction.h>
#include <vtkSphereSource.h>
#include <vtkUnstructuredGrid.h>

int main(int, char*[])
{
  vtkNew<vtkNamedColors> namedColors;

  // If we try to use a PointSource with vtkBridgeDataSet, an error is produced:
  //    vtkBridgeCell.cxx:141: virtual int vtkBridgeCell::GetType(): Assertion
  //    `"check: impossible case" && 0' failed.
  // There does not seem to be a case to handle VTK_VERTEX (which is what is
  // produced by PointSource) in vtkBridgeDataSet.
  //  vtkNew<vtkPointSource> pointSource;
  //  pointSource->SetNumberOfPoints(100);
  //  pointSource->SetRadius(1.0);
  //  pointSource->Update();

  vtkNew<vtkSphereSource> sphereSource;
  sphereSource->SetRadius(5);
  sphereSource->SetThetaResolution(10);
  sphereSource->SetPhiResolution(10);
  sphereSource->Update();

  // Add ids to the points and cells of the sphere
  vtkNew<vtkIdFilter> idFilter;
  idFilter->SetInputConnection(sphereSource->GetOutputPort());
  idFilter->Update();

  // Create a plane to clip with
  vtkNew<vtkPlane> plane;
  plane->SetOrigin(0, 0, 0);
  plane->SetNormal(1, 1, 1);

  // Convert the DataSet to a GenericDataSet
  vtkNew<vtkBridgeDataSet> bridgeDataSet;
  bridgeDataSet->SetDataSet(idFilter->GetOutput());

  vtkNew<vtkGenericClip> clipper;
  clipper->SetClipFunction(plane);
  clipper->SetInputData(bridgeDataSet);
  clipper->Update();

  // Get the clipped cell ids
  vtkUnstructuredGrid* clipped = clipper->GetOutput();
  vtkIdTypeArray* originalIds = dynamic_cast<vtkIdTypeArray*>(
      clipped->GetCellData()->GetArray("vtkIdFilter_Ids"));
  for (vtkIdType i = 0; i < originalIds->GetNumberOfTuples(); ++i)
  {
    std::cout << "new id " << i << ", original id " << originalIds->GetValue(i)
              << std::endl;
  }

  // Create a mapper and actor for clipped points
  vtkNew<vtkDataSetMapper> mapper;
  mapper->SetInputConnection(clipper->GetOutputPort());
  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);

  // Create a mapper and actor for clipping function
  vtkNew<vtkSampleFunction> sample;
  sample->SetSampleDimensions(20, 20, 20);
  sample->SetImplicitFunction(plane);
  double value = 10.0;
  double xmin = -value, xmax = value, ymin = -value, ymax = value,
         zmin = -value, zmax = value;
  sample->SetModelBounds(xmin, xmax, ymin, ymax, zmin, zmax);

  // Create the 0 isosurface
  vtkNew<vtkContourFilter> contours;
  contours->SetInputConnection(sample->GetOutputPort());
  contours->GenerateValues(1, 1, 1);

  // Map the contours to graphical primitives
  vtkNew<vtkPolyDataMapper> contourMapper;
  contourMapper->SetInputConnection(contours->GetOutputPort());
  contourMapper->SetScalarRange(0.0, 1.2);

  // Create an actor for the sphere
  vtkNew<vtkActor> sphereActor;
  sphereActor->SetMapper(contourMapper);

  // Create a renderer, render window, and interactor
  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);

  // Add the actor to the scene
  renderer->AddActor(actor);
  renderer->AddActor(sphereActor);
  renderer->SetBackground(namedColors->GetColor3d("Burlywood").GetData());
  renderer->UseHiddenLineRemovalOn();
  // Render and interact
  renderWindow->SetWindowName("GenericClip");
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(GenericClip)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersCore
  vtkFiltersGeneric
  vtkFiltersSources
  vtkImagingHybrid
  vtkInteractionStyle
  vtkRenderingContextOpenGL2
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingGL2PSOpenGL2
  vtkRenderingOpenGL2
  vtkTestingGenericBridge
  QUIET
)

if (NOT VTK_FOUND)
  message("Skipping GenericClip: ${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(GenericClip MACOSX_BUNDLE GenericClip.cxx )
  target_link_libraries(GenericClip PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(GenericClip MACOSX_BUNDLE GenericClip.cxx )
  target_link_libraries(GenericClip PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS GenericClip
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build GenericClip

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

cd GenericClip/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:

./GenericClip

WINDOWS USERS

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