>> Can Cubit produce MED or be converted to MED? I haven't used it, but it >> sounds like there is some mesh generation software available for it.
Cubit does not support MED out of the box (as of 15.0). They may have a plugin, not sure. > Gmsh can convert anything it can read to MED I believe. I have not used meshes in MED format but I think it doesn't handle/represent solid geometries. GMsh uses OpenCascade primarily under the hood. AFAIK, they've been using it for a while. So they should be able to load step/brep/iges format through the OCC interface. But if we are talking about meshes, then they may have a MED format writer that preserves second-order accuracy in meshes. In which case, their native "msh" format may support this too. Vijay On Fri, Jun 2, 2017 at 9:56 PM, Matthew Knepley <[email protected]> wrote: > On Fri, Jun 2, 2017 at 9:45 PM, Jed Brown <[email protected]> wrote: >> >> Matthew Knepley <[email protected]> writes: >> >> > On Fri, Jun 2, 2017 at 8:38 PM, Jed Brown <[email protected]> wrote: >> > >> >> Matthew Knepley <[email protected]> writes: >> >> >> >> > On Fri, Jun 2, 2017 at 7:55 PM, Jed Brown <[email protected]> wrote: >> >> > >> >> >> Matthew Knepley <[email protected]> writes: >> >> >> >> >> >> > On Fri, Jun 2, 2017 at 5:04 PM, Alberto Paganini < >> >> >> > [email protected]> wrote: >> >> >> > >> >> >> >> Dear PETSc developers, >> >> >> >> >> >> >> >> I'm Alberto and I'm a user of the finite element library >> >> >> >> Firedrake, >> >> >> >> which relies on DMPlex to import meshes. >> >> >> >> >> >> >> > >> >> >> > Great. >> >> >> > >> >> >> > >> >> >> >> In order to use higher-order FEs, it is desirable to import >> >> higher-order >> >> >> >> meshes. >> >> >> >> >> >> >> > >> >> >> > I really do not like that term. Let me try and convince you that >> >> >> > it is >> >> >> > wrong. The topology of the >> >> >> > mesh is unchanged. You are only talking about the order of the >> >> >> > representation of the geometry >> >> >> > field. Thus, it is not the mesh that is "higher order", but the >> >> geometry. >> >> >> > >> >> >> > >> >> >> >> I've been told that DMPlex does not offer this future (at >> >> >> >> present). >> >> >> >> >> >> >> > >> >> >> > Toby just merged this to master, so I think we can say that we >> >> >> > have >> >> alpha >> >> >> > support for this. How >> >> >> > does it work? We already have a coordinateDM and coordinates Vec, >> >> >> > so >> >> you >> >> >> > just choose a >> >> >> > higher order discretization for the DS inside the coordinateDM. >> >> >> > Does >> >> that >> >> >> > make sense? >> >> >> >> >> >> Can it load quadratic geometry from a file (ExodusII or otherwise)? >> >> >> >> >> > >> >> > If someone requests a given file format, we can do it. That's how we >> >> always >> >> > proceed. >> >> >> >> Okay. When people ask about higher order geometry for unstructured >> >> finite elements, I think that about 90% of the time they're really >> >> asking whether it can read quadratic geometry from a file. I hate that >> >> ExodusII is a cumbersome dependency, but it might be the most useful to >> >> add. This wouldn't be just cosmetically checking a box because this >> >> can >> >> make a big accuracy difference -- quadratic elements have a really hard >> >> time paying off for engineering problems if you don't also have >> >> quadratic geometry. >> >> >> > >> > ExodusII is perhaps the shittiest mesh format in existence. >> >> NASTRAN, ABAQUS, and the like are a pleasure by comparison? > > > It seems there is room at the top of the mountain of shit. > >> >> > For example, if we start reading ExodusII files with high order >> > geometry, that fucks up their definition of the topology because now >> > they only report C, the number of cells, and V+E+F, the number of >> > vertices and edges and faces. We could get lucky and have vertices >> > contiguous, but I cannot find anything in the manual that mandates >> > this. So we would overallocate, then reduce down to the right >> > topology, screwing up our fairly straightforward code right now. >> > >> > I would recommend the only non-stupid format I can name right now, the >> > MED format from the French CAD guys. Gmsh has switched over to using >> > it since their own format sucked worse than ExodusII. That is the only >> > one that it makes sense to write new code for. >> >> Can Cubit produce MED or be converted to MED? I haven't used it, but it >> sounds like there is some mesh generation software available for it. > > > Gmsh can convert anything it can read to MED I believe. > > Matt > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener > > http://www.caam.rice.edu/~mk51/
