OBBTreeIntersectWithLine

VTKExamples/Cxx/DataStructures/OBBTreeIntersectWithLine

Description vtkOBBTree returns ALL intersections with a line and the dataset. If you want the closest intersection, you must manually find it. In this example, we create a sphere and intersect a single line with it.

Code

OBBTreeIntersectWithLine.cxx

#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPointData.h>
#include <vtkLine.h>
#include <vtkOBBTree.h>

int main(int, char *[])
{
  vtkSmartPointer<vtkSphereSource> sphereSource = 
    vtkSmartPointer<vtkSphereSource>::New();
  sphereSource->Update();

  // Create the locator
  vtkSmartPointer<vtkOBBTree> tree = 
    vtkSmartPointer<vtkOBBTree>::New();
  tree->SetDataSet(sphereSource->GetOutput());
  tree->BuildLocator();

  // Intersect the locator with the line
  double lineP0[3] = {0.0, 0.0, 0.0};
  double lineP1[3] = {0.0, 0.0, 2.0};
  vtkSmartPointer<vtkPoints> intersectPoints = 
    vtkSmartPointer<vtkPoints>::New();

  tree->IntersectWithLine(lineP0, lineP1, intersectPoints, NULL);

  std::cout << "NumPoints: " << intersectPoints->GetNumberOfPoints()
            << std::endl;

  // Display list of intersections
  double intersection[3];
  for(int i = 0; i < intersectPoints->GetNumberOfPoints(); i++ )
  {
    intersectPoints->GetPoint(i, intersection);
    std::cout << "Intersection " << i << ": "
              << intersection[0] << ", "
              << intersection[1] << ", "
              << intersection[2] << std::endl;
  }

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(OBBTreeIntersectWithLine)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersGeneral
  vtkFiltersSources QUIET)
if (NOT VTK_FOUND)
  message("Skipping OBBTreeIntersectWithLine: ${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(OBBTreeIntersectWithLine MACOSX_BUNDLE OBBTreeIntersectWithLine.cxx )
  target_link_libraries(OBBTreeIntersectWithLine PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(OBBTreeIntersectWithLine MACOSX_BUNDLE OBBTreeIntersectWithLine.cxx )
  target_link_libraries(OBBTreeIntersectWithLine PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS OBBTreeIntersectWithLine
    MODULES ${VTK_LIBRARIES}
    )
endif () 

Download and Build OBBTreeIntersectWithLine

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

cd OBBTreeIntersectWithLine/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:

./OBBTreeIntersectWithLine

WINDOWS USERS

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