OctreeKClosestPoints

Question

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Code¶

OctreeKClosestPoints.cxx

#include <vtkNew.h>
#include <vtkOctreePointLocator.h>
#include <vtkPointSource.h>

int main(int, char*[])
{
  // Create some random points
  vtkNew<vtkPointSource> pointSource;
  pointSource->SetNumberOfPoints(10);
  pointSource->Update();

  // Create the tree
  vtkNew<vtkOctreePointLocator> octree;
  octree->SetDataSet(pointSource->GetOutput());
  octree->BuildLocator();

  // Find the k closest points to (0,0,0)
  vtkIdType k = 1;
  double testPoint[3] = {0.0, 0.0, 0.0};
  vtkNew<vtkIdList> result;

  octree->FindClosestNPoints(k, testPoint, result);

  for (vtkIdType i = 0; i < k; i++)
  {
    vtkIdType point_ind = result->GetId(i);
    double p[3];
    pointSource->GetOutput()->GetPoint(point_ind, p);
    std::cout << "Closest point " << i << ": Point " << point_ind << ": ("
              << p[0] << ", " << p[1] << ", " << p[2] << ")" << std::endl;
  }

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(OctreeKClosestPoints)

find_package(VTK COMPONENTS 
  CommonCore
  CommonDataModel
  FiltersSources
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "OctreeKClosestPoints: 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(OctreeKClosestPoints MACOSX_BUNDLE OctreeKClosestPoints.cxx )
  target_link_libraries(OctreeKClosestPoints PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS OctreeKClosestPoints
  MODULES ${VTK_LIBRARIES}
)

Download and Build OctreeKClosestPoints¶

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

cd OctreeKClosestPoints/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:

./OctreeKClosestPoints

WINDOWS USERS

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