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Can't save high-order mesh info...

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John
2012-12-15
2013-09-25
  • John
    John
    2012-12-15

    Hi All,

    I am using version 4.9.13 and am trying to generate a high-order surface mesh with curved elements for a simple sphere. I can generate the mesh fine in NETGEN, by setting the "element order" in the meshing options to whatever order I want. However, when I go to save the mesh as a ".vol" mesh, none of the high order information seems to be present.

    Also, if I export the mesh to any other format, there seems to be no information on the high-order representation.

    Are curved and high order elements supported in NETGEN? If so, how do I get the curved surface and high order node information?

    Thanks,
    John

     
  • Patrick
    Patrick
    2013-09-24

    I have the same Problem, does anyone have a solution??

     
  • Hi John,

    Netgen stores only the minimal mesh information in files, and recovers whatever it needs later when running the simulation. Curved elements need also full mesh topology (i.e. edges and faces), which would easily triple the size of mesh-files.

    Curving elements from the simulation package of course also requires the access to geometry (as does adaptive mesh refinement). Here you can use Netgen again.

    A compromise is to use second-order curved elements. These are represented as 10-node tets, and also stored in the mesh file.

    Exchanging high-order curved elements is more complex. We describe the curved elements by an arbitrary order hierarchical polynomial basis (Dubiner polynomials), just as hp-finite elements. You would have to implement the same basis in your simulation code.

    Anyway, if you want to write the curved elements to file, it's not terrible complex to implement that: You have to store the mesh topology (edges, and faces) from the class MeshTopology, and the curving-coefficients for the hierarchical basis, available in the class CurvedElements.

    best,
    Joachim