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OBBTreeIntersectWithLine

Repository source: 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.

Question

If you have a question about this example, please use the VTK Discourse Forum

Code

OBBTreeIntersectWithLine.cxx

#include <vtkNew.h>
#include <vtkOBBTree.h>
#include <vtkPoints.h>
#include <vtkSphereSource.h>

int main(int, char*[])
{
  vtkNew<vtkSphereSource> sphereSource;
  sphereSource->Update();

  // Create the locator
  vtkNew<vtkOBBTree> tree;
  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};
  vtkNew<vtkPoints> intersectPoints;

  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 3.12 FATAL_ERROR)

project(OBBTreeIntersectWithLine)

find_package(VTK COMPONENTS 
  CommonCore
  FiltersGeneral
  FiltersSources
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "OBBTreeIntersectWithLine: 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(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}
)

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.