PointInsideObject2
VTKExamples/Cxx/PolyData/PointInsideObject2
Description¶
This example creates a volume (convex hull-ish) out of a mesh object. It then uses FindCell (which determines if a point is inside of a cell) to determine if a point is inside of any of the 3D cells created by Delaunay3D or not. This could potentially lead to false positives - that is, points that are outside the mesh but inside the convex hull.
Question
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Code¶
PointInsideObject2.cxx
#include <vtkProperty.h> #include <vtkCellArray.h> #include<vtkPolyDataMapper.h> #include<vtkDelaunay3D.h> #include <vtkSphereSource.h> #include <vtkPolyData.h> #include <vtkSmartPointer.h> #include <vtkPolyDataMapper.h> #include <vtkActor.h> #include <vtkRenderWindow.h> #include <vtkRenderer.h> #include <vtkRenderWindowInteractor.h> #include <vtkUnstructuredGrid.h> #include <vtkVertexGlyphFilter.h> int main(int , char *[]) { // Create a sphere vtkSmartPointer<vtkSphereSource> bigSphereSource = vtkSmartPointer<vtkSphereSource>::New(); bigSphereSource->SetCenter(0.0, 0.0, 0.0); bigSphereSource->SetRadius(4); bigSphereSource->SetThetaResolution(20); bigSphereSource->SetPhiResolution(20); bigSphereSource->Update(); vtkSmartPointer<vtkPolyDataMapper> bigSphereMapper = vtkSmartPointer<vtkPolyDataMapper>::New(); bigSphereMapper->SetInputConnection(bigSphereSource->GetOutputPort()); vtkSmartPointer<vtkActor> bigSphereActor = vtkSmartPointer<vtkActor>::New(); bigSphereActor->SetMapper(bigSphereMapper); bigSphereActor->GetProperty()->SetOpacity(.5); vtkSmartPointer<vtkSphereSource> smallSphereSource = vtkSmartPointer<vtkSphereSource>::New(); smallSphereSource->SetCenter(1, 2, 1); smallSphereSource->SetRadius(2); smallSphereSource->SetThetaResolution(20); smallSphereSource->SetPhiResolution(20); smallSphereSource->Update(); vtkSmartPointer<vtkPolyDataMapper> smallSphereMapper = vtkSmartPointer<vtkPolyDataMapper>::New(); smallSphereMapper->SetInputConnection(smallSphereSource->GetOutputPort()); vtkSmartPointer<vtkActor> smallSphereActor = vtkSmartPointer<vtkActor>::New(); smallSphereActor->SetMapper(smallSphereMapper); vtkSmartPointer<vtkPoints> pointsInside = vtkSmartPointer<vtkPoints>::New(); vtkSmartPointer<vtkPolyData> polyDataInside = vtkSmartPointer<vtkPolyData>::New(); double point[3]; vtkSmartPointer<vtkDelaunay3D> delaunay3D = vtkSmartPointer<vtkDelaunay3D>::New(); delaunay3D->SetInputConnection (bigSphereSource->GetOutputPort()); delaunay3D->Update(); for(vtkIdType i = 0; i < smallSphereSource->GetOutput()->GetNumberOfPoints(); i++) { smallSphereSource->GetOutput()->GetPoint(i,point); double pcoords[3]; // The number of weights >= max number of nodes in each cell double weights[4]; int subId; vtkIdType cellId = delaunay3D->GetOutput()->FindCell(point,NULL, 0, .1,subId, pcoords, weights); if (cellId>=0) { std::cout << "In cell " << cellId << std::endl; std::cout << "inside" << std::endl; pointsInside->InsertNextPoint(point); } else { std::cout << "outside" << std::endl; } } polyDataInside->SetPoints(pointsInside); vtkSmartPointer<vtkVertexGlyphFilter> vertexGlyphFilter = vtkSmartPointer<vtkVertexGlyphFilter>::New(); vertexGlyphFilter->SetInputData(polyDataInside); vertexGlyphFilter->Update(); // Mapper and actor for points inside vtkSmartPointer<vtkPolyDataMapper> pointsInsideMapper = vtkSmartPointer<vtkPolyDataMapper>::New(); pointsInsideMapper->SetInputConnection(vertexGlyphFilter->GetOutputPort()); vtkSmartPointer<vtkActor> pointsInsideActor = vtkSmartPointer<vtkActor>::New(); pointsInsideActor->SetMapper(pointsInsideMapper); pointsInsideActor->GetProperty()->SetPointSize(6); pointsInsideActor->GetProperty()->SetColor(1,0,1); vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New(); vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->AddRenderer(renderer); vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); renderWindowInteractor->SetRenderWindow(renderWindow); renderer->AddActor(smallSphereActor); renderer->AddActor(bigSphereActor); renderer->AddActor(pointsInsideActor); renderer->SetBackground(.3, .6, .3); // Background color green renderWindow->Render(); renderWindowInteractor->Start(); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR) project(PointInsideObject2) find_package(VTK COMPONENTS vtkCommonCore vtkCommonDataModel vtkFiltersCore vtkFiltersGeneral vtkFiltersSources vtkInteractionStyle vtkRenderingCore vtkRenderingFreeType vtkRenderingOpenGL2 QUIET) if (NOT VTK_FOUND) message("Skipping PointInsideObject2: ${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(PointInsideObject2 MACOSX_BUNDLE PointInsideObject2.cxx ) target_link_libraries(PointInsideObject2 PRIVATE ${VTK_LIBRARIES}) else () # include all components add_executable(PointInsideObject2 MACOSX_BUNDLE PointInsideObject2.cxx ) target_link_libraries(PointInsideObject2 PRIVATE ${VTK_LIBRARIES}) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS PointInsideObject2 MODULES ${VTK_LIBRARIES} ) endif ()
Download and Build PointInsideObject2¶
Click here to download PointInsideObject2 and its CMakeLists.txt file. Once the tarball PointInsideObject2.tar has been downloaded and extracted,
cd PointInsideObject2/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:
./PointInsideObject2
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.