From: Martin Lüthi <luethi@va...> - 2008-02-25 07:27:07
> When you have a mesh consisting of HEX20 elements, libmesh doesn't correctly
> save to file in Gmsh format (.msh). This only happens with HEX20, all other
> element types are ok.
This might well be. There is a TODO item in the source code asking
what to do on saving HEX20. If I remember correctly, HEX20 was not
implemented in GMSH when I was tinkering with that code.
> Comparing with the output of a mesh consisting of other elements (HEX27, for
> example), I found that the problem is in the "$Elements" section. There are
> two problems actually:
> 1- the second field (id of the element type) is 101, it should be 17
> 2- the order of the nodes (of 1 element only) is:
> "2 3 4 5 6 7 8 9 10 11 12 17 18 19 20 13 14 15 16 17"
> But it should be
> "1 2 3 4 5 6 7 8 9 12 13 10 14 11 15 16 17 20 18 19"
Great. From the link you gave it seems that now also PRISM15 elements
are supported (another TODO item in the code). Patching the code
should be trivial, maybe you'll commit a diff -c to the developers?
From: Paulo Vieira <paulovieira.ml@gm...> - 2008-02-27 17:23:18
2008/2/25, Martin L üthi <luethi@...>:
>> When you have a mesh consisting of HEX20 elements, libmesh doesn't
>> correctly save to file in Gmsh format (.msh). This only happens with HEX20,
>> all other element types are ok.
> This might well be. There is a TODO item in the source code asking
> what to do on saving HEX20. If I remember correctly, HEX20 was not
> implemented in GMSH when I was tinkering with that code.
I should have taken a look at the source code before but I assumed
that if the element type was available for that output format then
everything should be ok. Hex20 is working now, simple fix. In some
days I'll send a patch to fix pyramids and tet8 as well.
In fact I'm using another software to visualize the mesh and the
results - GID ( http://gid.cimne.upc.es/ ). It's more powerful than
Gmsh, though it's not free (but the free version it's good enough for
simple tasks, or you can request a 1 month password to get it fully
working). So far I'm just doing a conversion GID format <-> XDA format
to interact with Libmesh, but I'll try to add this feature in the
future, so there will be one more format/software available to work