ConvexPointSet

vtk-examples/Cxx/GeometricObjects/ConvexPointSet

Description¶

vtkConvexPointSet object represents a 3D cell defined by a convex set of points. An example of such a cell is an octant (from an octree).

vtkConvexPointSet uses the ordered triangulations approach (vtkOrderedTriangulator) to create triangulations guaranteed to be compatible across shared faces.

Other languages

See (Python), (Java)

Question

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

Code¶

ConvexPointSet.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkConvexPointSet.h>
#include <vtkDataSetMapper.h>
#include <vtkGlyph3DMapper.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>
#include <vtkUnstructuredGrid.h>

int main(int, char*[])
{
  vtkNew<vtkConvexPointSet> cps;
  vtkNew<vtkPoints> points;
  points->InsertNextPoint(0, 0, 0);
  points->InsertNextPoint(1, 0, 0);
  points->InsertNextPoint(1, 1, 0);
  points->InsertNextPoint(0, 1, 0);
  points->InsertNextPoint(0, 0, 1);
  points->InsertNextPoint(1, 0, 1);
  points->InsertNextPoint(1, 1, 1);
  points->InsertNextPoint(0, 1, 1);
  points->InsertNextPoint(0.5, 0, 0);
  points->InsertNextPoint(1, 0.5, 0);
  points->InsertNextPoint(0.5, 1, 0);
  points->InsertNextPoint(0, 0.5, 0);
  points->InsertNextPoint(0.5, 0.5, 0);

  for (int i = 0; i < 13; ++i)
  {
    cps->GetPointIds()->InsertId(i, i);
  }

  vtkNew<vtkUnstructuredGrid> ug;
  ug->Allocate(1, 1);
  ug->InsertNextCell(cps->GetCellType(), cps->GetPointIds());
  ug->SetPoints(points);

  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkDataSetMapper> mapper;
  mapper->SetInputData(ug);

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("Tomato").GetData());
  actor->GetProperty()->SetLineWidth(3);
  actor->GetProperty()->EdgeVisibilityOn();

  // Glyph the points
  vtkNew<vtkSphereSource> sphere;
  sphere->SetPhiResolution(21);
  sphere->SetThetaResolution(21);
  sphere->SetRadius(.03);

  // Create a polydata to store everything in
  vtkNew<vtkPolyData> polyData;
  polyData->SetPoints(points);

  vtkNew<vtkGlyph3DMapper> pointMapper;
  pointMapper->SetInputData(polyData);
  pointMapper->SetSourceConnection(sphere->GetOutputPort());

  vtkNew<vtkActor> pointActor;
  pointActor->SetMapper(pointMapper);
  pointActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());

  // Create a renderer, render window, and interactor
  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->SetWindowName("ConvexPointSet");
  renderWindow->AddRenderer(renderer);
  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);

  // Add the actors to the scene
  renderer->AddActor(actor);
  renderer->AddActor(pointActor);
  renderer->SetBackground(colors->GetColor3d("Silver").GetData());

  renderer->ResetCamera();
  renderer->GetActiveCamera()->Azimuth(210);
  renderer->GetActiveCamera()->Elevation(30);
  renderer->ResetCameraClippingRange();

  // Render and interact
  renderWindow->SetSize(640, 480);
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ConvexPointSet)

find_package(VTK COMPONENTS 
)

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

Download and Build ConvexPointSet¶

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

cd ConvexPointSet/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:

./ConvexPointSet

WINDOWS USERS

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