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# TransformActorCollection

VTKEx/Cxx/Visualization/TransformActorCollection

Question

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### Code

TransformActorCollection.cxx

    #include <vtkSmartPointer.h>
    #include <vtkConeSource.h>
    #include <vtkSphereSource.h>
    #include <vtkCubeSource.h>
    #include <vtkTransform.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkActorCollection.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();

      // Create a cone
      vtkSmartPointer<vtkConeSource> coneSource =
        vtkSmartPointer<vtkConeSource>::New();
      coneSource->SetHeight(3);

      vtkSmartPointer<vtkPolyDataMapper> coneMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      coneMapper->SetInputConnection(coneSource->GetOutputPort());
      vtkSmartPointer<vtkActor> coneActor =
        vtkSmartPointer<vtkActor>::New();
      coneActor->SetMapper(coneMapper);

      // Create a cube
      vtkSmartPointer<vtkCubeSource> cubeSource =
        vtkSmartPointer<vtkCubeSource>::New();

      vtkSmartPointer<vtkPolyDataMapper> cubeMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      cubeMapper->SetInputConnection(cubeSource->GetOutputPort());
      vtkSmartPointer<vtkActor> cubeActor =
        vtkSmartPointer<vtkActor>::New();
      cubeActor->SetMapper(cubeMapper);

      // Create a sphere
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();

      vtkSmartPointer<vtkPolyDataMapper> sphereMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      sphereMapper->SetInputConnection(sphereSource->GetOutputPort());
      vtkSmartPointer<vtkActor> sphereActor =
        vtkSmartPointer<vtkActor>::New();
      sphereActor->SetMapper(sphereMapper);
      renderer->AddActor(sphereActor);

      vtkSmartPointer<vtkActorCollection> actorCollection =
        vtkSmartPointer<vtkActorCollection>::New();
      actorCollection->AddItem(cubeActor);
      actorCollection->AddItem(coneActor);
      actorCollection->InitTraversal();

      vtkSmartPointer<vtkTransform> transform =
        vtkSmartPointer<vtkTransform>::New();
      transform->PostMultiply(); //this is the key line
      transform->Translate(5.0, 0, 0);

      //actorCollection->SetUserTransform(transform);

      for(vtkIdType i = 0; i < actorCollection->GetNumberOfItems(); i++)
      {
        vtkActor* actor = actorCollection->GetNextActor();
        actor->SetUserTransform(transform);
        renderer->AddActor(actor);
      }

      // Create a renderer, render window, and interactor

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      // Add the actor to the scene
      renderer->SetBackground(.2, .3, .4);

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(TransformActorCollection)

    find_package(VTK COMPONENTS
      vtkvtkCommonCore
      vtkvtkCommonDataModel
      vtkvtkCommonTransforms
      vtkvtkFiltersSources
      vtkvtkInteractionStyle
      vtkvtkRenderingContextOpenGL2
      vtkvtkRenderingCore
      vtkvtkRenderingFreeType
      vtkvtkRenderingGL2PSOpenGL2
      vtkvtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping TransformActorCollection: ${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(TransformActorCollection MACOSX_BUNDLE TransformActorCollection.cxx )
      target_link_libraries(TransformActorCollection PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(TransformActorCollection MACOSX_BUNDLE TransformActorCollection.cxx )
      target_link_libraries(TransformActorCollection PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS TransformActorCollection
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build TransformActorCollection

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

    cd TransformActorCollection/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:

    ./TransformActorCollection

WINDOWS USERS

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