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AlignFrames

vtk-examples/Cxx/PolyData/AlignFrames

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Code

AlignFrames.cxx

#include <vtkLandmarkTransform.h>
#include <vtkMath.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkTransform.h>
#include <vtkTransformFilter.h>
#include <vtkVertexGlyphFilter.h>
#include <vtkXMLPolyDataWriter.h>

namespace {
struct Frame
{
  Frame(float o[3], float x[3], float y[3], float z[3])
  {
    this->SetOrigin(o);
    this->SetXDirection(x);
    this->SetYDirection(y);
    this->SetZDirection(z);

    std::cout << "Origin: " << this->origin[0] << " " << this->origin[1] << " "
              << this->origin[2] << std::endl;
    std::cout << "xDirection: " << this->xDirection[0] << " "
              << this->xDirection[1] << " " << this->xDirection[2] << std::endl;
    std::cout << "yDirection: " << this->yDirection[0] << " "
              << this->yDirection[1] << " " << this->yDirection[2] << std::endl;
    std::cout << "zDirection: " << this->zDirection[0] << " "
              << this->zDirection[1] << " " << this->zDirection[2] << std::endl;
  }

  void ApplyTransform(vtkTransform* transform, std::string filename)
  {
    vtkNew<vtkPolyData> polydata;
    CreatePolydata(polydata);

    vtkNew<vtkTransformFilter> transformFilter;
    transformFilter->SetInputData(polydata);
    transformFilter->SetTransform(transform);
    transformFilter->Update();

    vtkNew<vtkXMLPolyDataWriter> writer;
    writer->SetFileName(filename.c_str());
    writer->SetInputConnection(transformFilter->GetOutputPort());
    writer->Write();
  }

  void CreatePolydata(vtkPolyData* polydata)
  {
    vtkNew<vtkPoints> points;

    points->InsertNextPoint(this->origin);
    float x[3];
    vtkMath::Add(this->origin, this->xDirection, x);
    points->InsertNextPoint(x);
    float y[3];
    vtkMath::Add(this->origin, this->yDirection, y);
    points->InsertNextPoint(y);
    float z[3];
    vtkMath::Add(this->origin, this->zDirection, z);
    points->InsertNextPoint(z);

    polydata->SetPoints(points);

    vtkNew<vtkVertexGlyphFilter> vertexGlyphFilter;
    vertexGlyphFilter->AddInputData(polydata);
    vertexGlyphFilter->Update();

    polydata->ShallowCopy(vertexGlyphFilter->GetOutput());
  }

  void Write(std::string filename)
  {
    vtkNew<vtkPolyData> polydata;
    CreatePolydata(polydata);

    vtkNew<vtkXMLPolyDataWriter> writer;
    writer->SetFileName(filename.c_str());
    writer->SetInputData(polydata);
    writer->Write();
  }

  float origin[3];
  float xDirection[3];
  float yDirection[3];
  float zDirection[3];

  void SetOrigin(float o[3])
  {
    this->origin[0] = o[0];
    this->origin[1] = o[1];
    this->origin[2] = o[2];
  }

  void SetXDirection(float direction[3])
  {
    vtkMath::Normalize(direction);
    this->xDirection[0] = direction[0];
    this->xDirection[1] = direction[1];
    this->xDirection[2] = direction[2];
  }

  void SetYDirection(float direction[3])
  {
    vtkMath::Normalize(direction);
    this->yDirection[0] = direction[0];
    this->yDirection[1] = direction[1];
    this->yDirection[2] = direction[2];
  }

  void SetZDirection(float direction[3])
  {
    vtkMath::Normalize(direction);
    this->zDirection[0] = direction[0];
    this->zDirection[1] = direction[1];
    this->zDirection[2] = direction[2];
  }
};

void AlignFrames(Frame sourceFrame, Frame destinationFrame,
                 vtkTransform* transform);
} // namespace

int main(int, char*[])
{
  float frame1origin[3] = {0, 0, 0};
  float frame1XDirection[3] = {1, 0, 0};
  float frame1YDirection[3] = {0, 1, 0};
  std::cout << frame1YDirection[0] << " " << frame1YDirection[1] << " "
            << frame1YDirection[2] << std::endl;
  float frame1ZDirection[3] = {0, 0, 1};
  Frame frame1(frame1origin, frame1XDirection, frame1YDirection,
               frame1ZDirection);
  frame1.Write("frame1.vtp");

  float frame2origin[3] = {0, 0, 0};
  float frame2XDirection[3] = {.707f, .707f, 0};
  float frame2YDirection[3] = {-.707f, .707f, 0};
  float frame2ZDirection[3] = {0, 0, 1};
  Frame frame2(frame2origin, frame2XDirection, frame2YDirection,
               frame2ZDirection);
  frame2.Write("frame2.vtp");

  vtkNew<vtkTransform> transform;
  AlignFrames(frame2, frame1, transform); // Brings frame2 to frame1

  // std::cout << *transform << std::endl;

  frame2.ApplyTransform(transform, "transformed.vtp");

  return EXIT_SUCCESS;
}

namespace {
void AlignFrames(Frame sourceFrame, Frame targetFrame, vtkTransform* transform)
{
  // This function takes two frames and finds the matrix M between them.

  vtkNew<vtkLandmarkTransform> landmarkTransform;

  // Setup source points
  vtkNew<vtkPoints> sourcePoints;

  sourcePoints->InsertNextPoint(sourceFrame.origin);
  float sourceX[3];
  vtkMath::Add(sourceFrame.origin, sourceFrame.xDirection, sourceX);
  sourcePoints->InsertNextPoint(sourceX);
  float sourceY[3];
  vtkMath::Add(sourceFrame.origin, sourceFrame.yDirection, sourceY);
  sourcePoints->InsertNextPoint(sourceY);
  float sourceZ[3];
  vtkMath::Add(sourceFrame.origin, sourceFrame.zDirection, sourceZ);
  sourcePoints->InsertNextPoint(sourceZ);

  // Setup target points
  vtkNew<vtkPoints> targetPoints;

  targetPoints->InsertNextPoint(targetFrame.origin);
  float targetX[3];
  vtkMath::Add(targetFrame.origin, targetFrame.xDirection, targetX);
  targetPoints->InsertNextPoint(targetX);
  float targetY[3];
  vtkMath::Add(targetFrame.origin, targetFrame.yDirection, targetY);
  targetPoints->InsertNextPoint(targetY);
  float targetZ[3];
  vtkMath::Add(targetFrame.origin, targetFrame.zDirection, targetZ);
  targetPoints->InsertNextPoint(targetZ);

  landmarkTransform->SetSourceLandmarks(sourcePoints);
  landmarkTransform->SetTargetLandmarks(targetPoints);
  landmarkTransform->SetModeToRigidBody();
  landmarkTransform->Update();

  vtkMatrix4x4* M = landmarkTransform->GetMatrix();

  transform->SetMatrix(M);
}
} // namespace

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(AlignFrames)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  vtkCommonTransforms
  vtkFiltersGeneral
  vtkIOXML
  QUIET
)

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

Download and Build AlignFrames

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

cd AlignFrames/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:

./AlignFrames

WINDOWS USERS

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