ShrinkCube

vtk-examples/Cxx/GeometricObjects/ShrinkCube

Description¶

Generates a cube using vtkCubeSource, then a shrink filter is applied. vtkShrinkFilter object shrinks cells composing an arbitrary data set towards their centroid. The centroid of a cell is computed as the average position of the cell points. Shrinking results in disconnecting the cells from one another.

Seealso

TessellatedBoxSource generates multiple quads or triangles per side.

Info

See Figure 5-17 in Chapter 5 the VTK Textbook.

Other languages

See (Python), (Java)

Question

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

Code¶

ShrinkCube.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkCubeSource.h>
#include <vtkDataSetMapper.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyData.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkShrinkFilter.h>

int main(int, char*[])
{
  // Create a cube.
  vtkNew<vtkCubeSource> cubeSource;

  vtkNew<vtkShrinkFilter> shrink;
  shrink->SetInputConnection(cubeSource->GetOutputPort());
  shrink->SetShrinkFactor(.9);

  // Create a mapper and actor.
  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkDataSetMapper> mapper;
  mapper->SetInputConnection(shrink->GetOutputPort());

  vtkNew<vtkProperty> back;
  back->SetColor(colors->GetColor3d("Tomato").GetData());

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->EdgeVisibilityOn();
  actor->GetProperty()->SetColor(colors->GetColor3d("Banana").GetData());
  actor->SetBackfaceProperty(back);

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

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

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

  // Render and interact
  renderWindow->SetWindowName("ShrinkCube");
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ShrinkCube)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersGeneral
  vtkFiltersSources
  vtkInteractionStyle
  vtkRenderingContextOpenGL2
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingGL2PSOpenGL2
  vtkRenderingOpenGL2
  QUIET
)

if (NOT VTK_FOUND)
  message("Skipping ShrinkCube: ${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(ShrinkCube MACOSX_BUNDLE ShrinkCube.cxx )
  target_link_libraries(ShrinkCube PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ShrinkCube MACOSX_BUNDLE ShrinkCube.cxx )
  target_link_libraries(ShrinkCube PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ShrinkCube
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build ShrinkCube¶

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

cd ShrinkCube/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:

./ShrinkCube

WINDOWS USERS

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