[Insight-users] Converting simplex meshes to triangle meshes

[Luis Ibanez]

Hi Alexander,


Please use the


        itk::RegularSphereMeshSource

instead of the

        itk::SphereMeshSource

as illustrated in the example:


    Insight/Testing/Code/Algorithms
        itkSimplexMeshVolumeCalculatorTest.cxx



The RegularSphereMeshSource produces a triangulation by subdividing
an Icosahedron, which results in a regular size for all the triangles
in the sphere. The SphereMeshSource generates a triangulation using
the squares of a latitude/longitude partition of the sphere, and
results in very thin triangles in the sphere poles.



You may also want to look at the files:

  itkDeformableSimplexMesh3DBalloonForceFilterTest.cxx
  itkDeformableSimplexMesh3DFilterTest.cxx
  itkDeformableSimplexMesh3DGradientConstraintForceFilterTest.cxx

in the same directory.


and to the Application:

        InsightApplications
                 DeformableModelSimplexMesh/


You will probably be interested too in the following paper and
associated code in the Insight Journal:


        http://insight-journal.org/dspace/handle/1926/220


KWMeshVisu: A Mesh Visualization Tool for Shape Analysis
by
Oguz, Ipek
Gerig, Guido
Barre, Sebastien
Styner, Martin




   Regards,


      Luis



------------------------------------
Alexander Schmidt-Richberg wrote:
> Hello all,
> 
> I want to use the itk::DeformableSimplexMesh3DFilter for segmentation, 
> but I have problems converting simplex meshes to triangle meshes. In my 
> example code I simply generate a spherical triangle mesh, convert it to 
> a simplex mesh and then re-convert it to a triangle mesh.
> I get the following output:
> 
> Creating deformable mesh source...
> 
> Converting to simplex mesh...
> Converting to triangle mesh...
> error!!!
> Segmentation fault
> 
> 
> I hope someone can help me, please find my code below.
> 
> Thanks a lot,
> 
> Alexander
> 
> 
> typedef itk::DefaultStaticMeshTraits<double, 3, 3, double, double, 
> double> TriangleMeshTraits;
> typedef itk::DefaultStaticMeshTraits<double, 3, 3, double, double, 
> double> SimplexMeshTraits;
> typedef itk::Mesh<double,3,TriangleMeshTraits> TriangleMeshType;
> typedef itk::SimplexMesh<double,3, SimplexMeshTraits> SimplexMeshType;
> 
> typedef itk::SphereMeshSource<        TriangleMeshType > MeshSourceType;
> MeshSourceType::Pointer meshSource = MeshSourceType::New();
> 
> typedef itk::TriangleMeshToSimplexMeshFilter<        TriangleMeshType,
>        SimplexMeshType > TriangleToSimplexType;
> TriangleToSimplexType::Pointer triangleToSimplex = 
> TriangleToSimplexType::New();
> 
> typedef itk::SimplexMeshToTriangleMeshFilter<        SimplexMeshType,
>        TriangleMeshType > SimplexToTriangleType;
> SimplexToTriangleType::Pointer simplexToTriangle = 
> SimplexToTriangleType::New();
> 
> 
> std::cout << "Creating deformable mesh source..." << std::endl;
> // ... some parameters for the mesh source here
> meshSource->Update();
> 
> 
> std::cout << "Converting to simplex mesh... " << std::endl;
> triangleToSimplex->SetInput( meshSource->GetOutput() );
> try {
>  triangleToSimplex->Update();
> }
> catch( itk::ExceptionObject & excep )
> {
>  std::cerr << "Exception Caught!" << std::endl;
>  std::cerr << excep << std::endl;
> }
> 
> 
> std::cout << "Converting to triangle mesh... " << std::endl;
> simplexToTriangle->SetInput( triangleToSimplex->GetOutput() );
> try {
>  simplexToTriangle->Update();
> }
> catch( itk::ExceptionObject & excep )
> {
>  std::cerr << "Exception Caught!" << std::endl;
>  std::cerr << excep << std::endl;
> }
> 
> 
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