# TransformPolyData

VTKExamples/Cxx/Filtering/TransformPolyData

### Description

This example demonstrates how to apply a transform to a data set. It uses vtkTransformPolyDataFilter, but it can be replaced with vtkTransformFilter for different types of data sets, including vtkUnstructuredGrid and vtkStructuredGrid. vtkTransformFilter will work with vtkPolyData, too).

Other Languages

See (Python), (Java)

### Code

TransformPolyData.cxx

    #include <vtkSmartPointer.h>
    #include <vtkSphereSource.h>
    #include <vtkPolyData.h>
    #include <vtkTransform.h>
    #include <vtkTransformPolyDataFilter.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkProperty.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int, char *[])
    {
      // Create the polydata geometry

      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->Update();

      // Set up the actor to display the untransformed polydata

      vtkSmartPointer<vtkPolyDataMapper> originalMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      originalMapper->SetInputConnection(sphereSource->GetOutputPort());

      vtkSmartPointer<vtkActor> originalActor =
        vtkSmartPointer<vtkActor>::New();
      originalActor->SetMapper(originalMapper);
      originalActor->GetProperty()->SetColor(1,0,0);

      // Set up the transform filter

      vtkSmartPointer<vtkTransform> translation =
        vtkSmartPointer<vtkTransform>::New();
      translation->Translate(1.0, 2.0, 3.0);

      vtkSmartPointer<vtkTransformPolyDataFilter> transformFilter =
        vtkSmartPointer<vtkTransformPolyDataFilter>::New();
      transformFilter->SetInputConnection(sphereSource->GetOutputPort());
      transformFilter->SetTransform(translation);
      transformFilter->Update();

      // Set up the actor to display the transformed polydata

      vtkSmartPointer<vtkPolyDataMapper> transformedMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      transformedMapper->SetInputConnection(transformFilter->GetOutputPort());

      vtkSmartPointer<vtkActor> transformedActor =
        vtkSmartPointer<vtkActor>::New();
      transformedActor->SetMapper(transformedMapper);
      transformedActor->GetProperty()->SetColor(0,1,0);

      // Set up the rest of the visualization pipeline

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddActor(originalActor);
      renderer->AddActor(transformedActor);
      renderer->SetBackground(.3, .6, .3); // Set renderer's background color to green

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

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

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(TransformPolyData)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkCommonTransforms
      vtkFiltersGeneral
      vtkFiltersSources
      vtkInteractionStyle
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping TransformPolyData: ${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(TransformPolyData MACOSX_BUNDLE TransformPolyData.cxx )
      target_link_libraries(TransformPolyData PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(TransformPolyData MACOSX_BUNDLE TransformPolyData.cxx )
      target_link_libraries(TransformPolyData PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS TransformPolyData
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build TransformPolyData

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

    cd TransformPolyData/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:

    ./TransformPolyData

WINDOWS USERS

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