PolyDataConnectivityFilter LargestRegion
vtk-examples/Cxx/PolyData/PolyDataConnectivityFilter_LargestRegion
Description¶
This example uses vtkPolyDataConnectivityFilter to keep the largest connected region of a mesh. Note that this is based on the number of points, not the actual area of the region.
The original vtkPolyData is red, on top. The extracted region is yellow, on the bottom.
Note
Contrast this with PolyDataConnectivityFilter_SpecifiedRegion.
Note
Contributed by: Jinyoung Hwang
Other languages
See (CSharp)
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
PolyDataConnectivityFilter_LargestRegion.cxx
#include <vtkActor.h>
#include <vtkAppendPolyData.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyDataConnectivityFilter.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkNew.h>
#include <vtkSphereSource.h>
int main(int, char*[])
{
vtkNew<vtkNamedColors> colors;
// Small sphere
vtkNew<vtkSphereSource> sphereSource1;
sphereSource1->SetRadius(5);
// Large sphere
vtkNew<vtkSphereSource> sphereSource2;
sphereSource2->SetRadius(10);
sphereSource2->SetCenter(25, 0, 0);
sphereSource2->SetThetaResolution(10);
sphereSource2->SetPhiResolution(10);
vtkNew<vtkAppendPolyData> appendFilter;
appendFilter->AddInputConnection(sphereSource1->GetOutputPort());
appendFilter->AddInputConnection(sphereSource2->GetOutputPort());
vtkNew<vtkPolyDataConnectivityFilter> connectivityFilter;
connectivityFilter->SetInputConnection(appendFilter->GetOutputPort());
connectivityFilter->SetExtractionModeToLargestRegion();
// Create a mapper and actor for original data
vtkNew<vtkPolyDataMapper> originalMapper;
originalMapper->SetInputConnection(appendFilter->GetOutputPort());
vtkNew<vtkActor> originalActor;
originalActor->SetMapper(originalMapper);
originalActor->GetProperty()->SetColor(
colors->GetColor3d("Tomato").GetData());
// Create a mapper and actor for extracted data
vtkNew<vtkPolyDataMapper> extractedMapper;
extractedMapper->SetInputConnection(connectivityFilter->GetOutputPort());
extractedMapper->Update();
vtkNew<vtkActor> extractedActor;
extractedActor->GetProperty()->SetColor(
colors->GetColor3d("Banana").GetData());
extractedActor->SetMapper(extractedMapper);
extractedActor->SetPosition(0, -20, 0);
// Visualization
vtkNew<vtkRenderer> renderer;
renderer->AddActor(originalActor);
renderer->AddActor(extractedActor);
renderer->GradientBackgroundOn();
renderer->SetBackground(colors->GetColor3d("Gold").GetData());
renderer->SetBackground2(colors->GetColor3d("Silver").GetData());
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetWindowName("PolyDataConnectivityFilter_LargestRegion");
vtkNew<vtkRenderWindowInteractor> interactor;
interactor->SetRenderWindow(renderWindow);
renderWindow->Render();
interactor->Initialize();
interactor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(PolyDataConnectivityFilter_LargestRegion)
find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkFiltersCore
vtkFiltersSources
vtkInteractionStyle
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
vtkRenderingOpenGL2
QUIET
)
if (NOT VTK_FOUND)
message("Skipping PolyDataConnectivityFilter_LargestRegion: ${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(PolyDataConnectivityFilter_LargestRegion MACOSX_BUNDLE PolyDataConnectivityFilter_LargestRegion.cxx )
target_link_libraries(PolyDataConnectivityFilter_LargestRegion PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(PolyDataConnectivityFilter_LargestRegion MACOSX_BUNDLE PolyDataConnectivityFilter_LargestRegion.cxx )
target_link_libraries(PolyDataConnectivityFilter_LargestRegion PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS PolyDataConnectivityFilter_LargestRegion
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build PolyDataConnectivityFilter_LargestRegion¶
Click here to download PolyDataConnectivityFilter_LargestRegion and its CMakeLists.txt file. Once the tarball PolyDataConnectivityFilter_LargestRegion.tar has been downloaded and extracted,
cd PolyDataConnectivityFilter_LargestRegion/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:
./PolyDataConnectivityFilter_LargestRegion
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.