PolyDataConnectivityFilter SpecifiedRegion
vtk-examples/Cxx/PolyData/PolyDataConnectivityFilter_SpecifiedRegion
Description¶
This example creates two spheres and combines them together into one polydata. The [vtkPolyData](https://www.vtk.org/doc/nightly/html/classvtkPolyData.html#details)ConnectivityFilter is used to find the two spheres as they are separate regions (disconnected). If region 0 is selected, the small sphere is extracted. If region 1 is selected, the large sphere is extracted.
The original vtkPolyData is red, on top. The extracted region is yellow, on the bottom.
Note
Contrast this with PolyDataConnectivityFilter_LargestRegion.
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_SpecifiedRegion.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 <vtkSphereSource.h>
#include <vtkNamedColors.h>
int main(int, char*[])
{
vtkNew<vtkNamedColors> colors;
vtkNew<vtkSphereSource> sphereSource1;
sphereSource1->SetRadius(5);
vtkNew<vtkSphereSource> sphereSource2;
sphereSource2->SetRadius(10);
sphereSource2->SetCenter(25, 0, 0);
vtkNew<vtkAppendPolyData> appendFilter;
appendFilter->AddInputConnection(sphereSource1->GetOutputPort());
appendFilter->AddInputConnection(sphereSource2->GetOutputPort());
vtkNew<vtkPolyDataConnectivityFilter> connectivityFilter;
connectivityFilter->SetInputConnection(appendFilter->GetOutputPort());
connectivityFilter->SetExtractionModeToSpecifiedRegions();
connectivityFilter->AddSpecifiedRegion(0); // select the region to extract
// here
connectivityFilter->Update();
// 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());
vtkNew<vtkActor> extractedActor;
extractedActor->SetMapper(extractedMapper);
extractedActor->GetProperty()->SetColor(
colors->GetColor3d("Banana").GetData());
extractedActor->SetPosition(0, -20, 0);
// create a renderer
vtkNew<vtkRenderer> renderer;
renderer->AddActor(originalActor);
renderer->AddActor(extractedActor);
renderer->GradientBackgroundOn();
renderer->SetBackground(colors->GetColor3d("Gold").GetData());
renderer->SetBackground2(colors->GetColor3d("Silver").GetData());
// create a render window
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetWindowName("PolyDataConnectivityFilter_SpecifiedRegion");
// create an interactor
vtkNew<vtkRenderWindowInteractor> interactor;
interactor->SetRenderWindow(renderWindow);
renderWindow->Render();
interactor->Initialize();
interactor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(PolyDataConnectivityFilter_SpecifiedRegion)
find_package(VTK COMPONENTS
CommonColor
CommonCore
FiltersCore
FiltersSources
InteractionStyle
RenderingContextOpenGL2
RenderingCore
RenderingFreeType
RenderingGL2PSOpenGL2
RenderingOpenGL2
)
if (NOT VTK_FOUND)
message(FATAL_ERROR "PolyDataConnectivityFilter_SpecifiedRegion: 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(PolyDataConnectivityFilter_SpecifiedRegion MACOSX_BUNDLE PolyDataConnectivityFilter_SpecifiedRegion.cxx )
target_link_libraries(PolyDataConnectivityFilter_SpecifiedRegion PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS PolyDataConnectivityFilter_SpecifiedRegion
MODULES ${VTK_LIBRARIES}
)
Download and Build PolyDataConnectivityFilter_SpecifiedRegion¶
Click here to download PolyDataConnectivityFilter_SpecifiedRegion and its CMakeLists.txt file. Once the tarball PolyDataConnectivityFilter_SpecifiedRegion.tar has been downloaded and extracted,
cd PolyDataConnectivityFilter_SpecifiedRegion/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_SpecifiedRegion
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.