ITK/Examples/Meshes/LoopTriangleCellSubdivision

Various filters exist to perform subdivision an itk::QuadEdgeMesh. This example demonstrates use of the itk::LoopTriangleCellSubdivionQuadEdgeMeshFilter.

Contributed by: Davis Vigneault

NOTE: This example uses code from an ITK remote module which must be turned on in the cmake configuration with:

Module_SubdivisionQuadEdgeMeshFilter:BOOL=ON

LoopTriangleCellSubdivision.cxx

<source lang="cpp">

1. include "itkRegularSphereMeshSource.h"
2. include "itkQuadEdgeMesh.h"
3. include "itkLoopTriangleCellSubdivisionQuadEdgeMeshFilter.h"
4. include "itkIterativeTriangleCellSubdivisionQuadEdgeMeshFilter.h"

// Dimension and coordinate type const unsigned int Dimension = 3; typedef float TCoordinate;

// Typedefs typedef itk::QuadEdgeMesh< TCoordinate, Dimension > TQEMesh; typedef itk::RegularSphereMeshSource< TQEMesh > TSphere; typedef itk::LoopTriangleCellSubdivisionQuadEdgeMeshFilter< TQEMesh, TQEMesh > TLoop; typedef itk::IterativeTriangleCellSubdivisionQuadEdgeMeshFilter< TQEMesh, TLoop > TSubdivision;

int main(int argc, char * argv[] ) {

 // Specify the number of times the loop subdivision should be applied
 const unsigned int NumberOfSubdivisions = 2;

 // Create a sphere and assign it to a TQEMesh variable
 TSphere::Pointer sphereSource = TSphere::New();
 sphereSource->Update();
 TQEMesh::Pointer sphere = sphereSource->GetOutput();

 // Assign the sphere to the subdivision filter
 TSubdivision::Pointer subdivision = TSubdivision::New();
 subdivision->SetResolutionLevels( NumberOfSubdivisions );
 subdivision->SetInput( sphere );
 subdivision->Update();

 // Assign the subdivided sphere to its own variable
 TQEMesh::Pointer subSphere = subdivision->GetOutput();

 // Compare points, edges, and faces for the original and subdivided spheres
 std::cout << "Original Sphere:" << std::endl;
 std::cout << "  Points: " << sphere->GetNumberOfPoints() << std::endl; // 66
 std::cout << "  Edges: " << sphere->GetNumberOfEdges() << std::endl; // 192
 std::cout << "  Faces: " << sphere->GetNumberOfFaces() << std::endl; // 128
 std::cout << std::endl;
 std::cout << "Divided Sphere: " << std::endl;
 std::cout << "  Points: " << subSphere->GetNumberOfPoints() << std::endl; // 1026
 std::cout << "  Edges: " << subSphere->GetNumberOfEdges() << std::endl; // 3072
 std::cout << "  Faces: " << subSphere->GetNumberOfFaces() << std::endl; // 2048

 return EXIT_SUCCESS;

}

</source>

CMakeLists.txt

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

project(LoopTriangleCellSubdivision)

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

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

endif()

add_executable(LoopTriangleCellSubdivision MACOSX_BUNDLE LoopTriangleCellSubdivision.cxx)

if( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(LoopTriangleCellSubdivision ITKReview ${ITK_LIBRARIES})

else( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(LoopTriangleCellSubdivision ${ITK_LIBRARIES})

endif( "${ITK_VERSION_MAJOR}" LESS 4 )

</syntaxhighlight>

Download and Build LoopTriangleCellSubdivision

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

cd LoopTriangleCellSubdivision/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:

./LoopTriangleCellSubdivision

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.