[MOAB-dev] Geodesic mesh representation

[Chris Eldred]

I have the mesh in a flat text file format- one file with vertex
coordinates, one file that lists the connectivity of faces to vertices
(ie for each face, what are the vertices that "bound" it).

Topologically, the mesh is 2D since the highest dimensionality element
is a face (bounded by edges). However, the mesh represents a
discretization of the surface of a sphere, so vertex coordinates are
3D (x,y,z). Since I am on the surface of a sphere of unit radius, I
could always go to a 2D coordinate representation in terms of angles
and just store the 3D coordinates as Tag values. Then everything would
be 2D (although the coordinates would be weird).

It is unclear to me how to define a 3D mesh from this, since there
really are no cells (elements of dimension = 3) in the mesh.

On Wed, Nov 6, 2013 at 4:44 PM, Iulian Grindeanu <iulian at mcs.anl.gov> wrote:
>
>
> ________________________________
>
> Dear Moab-Dev,
>
> I have a geodesic mesh (like MPAS or GCRM) and I was wondering what
> the best way to represent the mesh in MOAB was. It is topologically 2D
> but it is embedded in a 3D manifold (so vertex coordinates are x,y,z).
> I was thinking that I would treat the mesh as 2D, feed in "bogus"
> vertex coordinates and just use tags over the mesh elements to keep
> track of the actual mesh coordinates. This way, I keep the 2D
> topological structure (which is more important for my application
> anyways). Is this a good approach?
>
> Thanks,
> Chris Eldred
>
> --
> Chris Eldred
> DOE Computational Science Graduate Fellow
> Graduate Student, Atmospheric Science, Colorado State University
> B.S. Applied Computational Physics, Carnegie Mellon University, 2009
> chris.eldred at gmail.com / celdred at atmos.colostate.edu
>
> Probably I don't understand what you need :(
>
> What kind of format do you have ? netcdf? Is the mesh on a sphere / surface?
>
> The vertex coordinates are retrieved with "get_coords" methods, and set with
> set_coords methods, or use "coords_iterate" type methods in readUtil
> interface.
>
> Why not keep the full 3d mesh? what is so special about the 2d topological
> structure?
> Is it structured in any way? Can you use the MPAS reader or not?
>
> Iulian
>



-- 
Chris Eldred
DOE Computational Science Graduate Fellow
Graduate Student, Atmospheric Science, Colorado State University
B.S. Applied Computational Physics, Carnegie Mellon University, 2009
chris.eldred at gmail.com / celdred at atmos.colostate.edu