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.
Code
PointInsideObject2.cxx
#include <vtkVersion.h>
#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();
#if VTK_MAJOR_VERSION <= 5
vertexGlyphFilter->SetInputConnection(polyDataInside->GetProducerPort());
#else
vertexGlyphFilter->SetInputData(polyDataInside);
#endif
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 2.8)
PROJECT(PointInsideObject2)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(PointInsideObject2 MACOSX_BUNDLE PointInsideObject2.cxx)
target_link_libraries(PointInsideObject2 ${VTK_LIBRARIES})
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 PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.