ITK/Examples/Meshes/PointAndCellData

This example demonstrates how to add point and cell data to an itk::Mesh and write it to a .vtk mesh file. Please note that, currently, the only mesh file formats supported by ITK which allow for cell and point data are .vtk and .gii.

Contributed by: Davis Vigneault

PointAndCellData.cxx

<source lang="cpp">

// Include the relevant header files.

1. include "itkMesh.h"
2. include "itkRegularSphereMeshSource.h"
3. include "itkMeshFileWriter.h"

// We define the dimension and coordinate type... const unsigned int Dimension = 3; typedef float TCoordinate;

// ...and then typedef the mesh, sphere, and writer. typedef itk::Mesh< TCoordinate, Dimension > TMesh; typedef itk::RegularSphereMeshSource< TMesh > TSphere; typedef itk::MeshFileWriter< TMesh > TMeshWriter;

int main(int, char *[]) {

 // Create the sphere source. 
 TSphere::Pointer sphere = TSphere::New();
 sphere->Update();

 // We now assign it to a mesh pointer. 
 TMesh::Pointer mesh = sphere->GetOutput();
 
 // It is necessary to disconnect the mesh from the pipeline;
 // otherwise, the point and cell data will be deallocated
 // when we call "Update()" on the writer later in the program.
 mesh->DisconnectPipeline();

 // Let's assign a value to each of the mesh's points...
 for (unsigned int i = 0; i < mesh->GetNumberOfPoints(); ++i)
   mesh->SetPointData( i, 5.0 ); 

 // ...and assign a different value to each of the mesh's cells.
 for (unsigned int i = 0; i < mesh->GetNumberOfCells(); ++i)
   mesh->SetCellData( i, 10.0 );

 // We'll print out some data about the points...
 std::cout << mesh->GetNumberOfPoints() << std::endl; // 66
 std::cout << mesh->GetPointData()->Size() << std::endl; // 66
 std::cout << mesh->GetPointData()->ElementAt( 0 ) << std::endl << std::endl; // 5.0

 // ...and about the cells.
 std::cout << mesh->GetNumberOfCells() << std::endl; // 128
 std::cout << mesh->GetCellData()->Size() << std::endl; // 128
 std::cout << mesh->GetCellData()->ElementAt( 0 ) << std::endl << std::endl; // 10.0

 // Finally, we'll write the data to file.  Note that the only mesh file
 // formats supported by ITK which support cell and point data are .vtk and .gii.
 TMeshWriter::Pointer meshWriter = TMeshWriter::New();
 meshWriter->SetFileName( "mesh.vtk" );
 meshWriter->SetInput( mesh );
 meshWriter->Update();

 return EXIT_SUCCESS;

}

</source>

CMakeLists.txt

<syntaxhighlight lang="cmake"> cmake_minimum_required(VERSION 3.9.5)

project(PointAndCellData)

find_package(ITK REQUIRED) include(${ITK_USE_FILE}) if (ITKVtkGlue_LOADED)

 find_package(VTK REQUIRED)
 include(${VTK_USE_FILE})

endif()

add_executable(PointAndCellData MACOSX_BUNDLE PointAndCellData.cxx)

if( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(PointAndCellData ITKReview ${ITK_LIBRARIES})

else( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(PointAndCellData ${ITK_LIBRARIES})

endif( "${ITK_VERSION_MAJOR}" LESS 4 )

</syntaxhighlight>

Download and Build PointAndCellData

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

cd PointAndCellData/build

• If ITK is installed:

cmake ..

• If ITK is not installed but compiled on your system, you will need to specify the path to your ITK build:

cmake -DITK_DIR:PATH=/home/me/itk_build ..

Build the project:

make

and run it:

./PointAndCellData

WINDOWS USERS PLEASE NOTE: Be sure to add the ITK bin directory to your path. This will resolve the ITK dll's at run time.

Building All of the Examples

Many of the examples in the ITK Wiki Examples Collection require VTK. You can build all of the the examples by following these instructions. If you are a new VTK user, you may want to try the Superbuild which will build a proper ITK and VTK.

ItkVtkGlue

ITK >= 4

For examples that use QuickView (which depends on VTK), you must have built ITK with Module_ITKVtkGlue=ON.

ITK < 4

Some of the ITK Examples require VTK to display the images. If you download the entire ITK Wiki Examples Collection, the ItkVtkGlue directory will be included and configured. If you wish to just build a few examples, then you will need to download ItkVtkGlue and build it. When you run cmake it will ask you to specify the location of the ItkVtkGlue binary directory.