[Gmsh] make a hexa second order mesh out of a hexa first order mesh

Bernd Hahnebach gmsh at b75.ch
Fri May 13 07:16:51 CEST 2016


Found the culprit :-) but it does not solve my problem :-(

If either "Mesh --> set Order 2" or "Mesh -> Hight order tools" is  
used on a hexahedron8 it does not make a hexahedron20 but a  
hexahedron27 instead. Means a node is not only made on any edge center  
point but on any face center point too.

Neither unv nor inp export of GMSH support hexahedron27. A  
hexahedron20 can be exported to unv and inp and these files are fine.

This means back to the first question. Is it possible to make a  
hexahedron20 element out of an hexahedron8 in gmsh?

kind regards bernd

attached a hexa20.unv and hexa8.unv to test with.


Zitat von Bernd Hahnebach <gmsh at b75.ch>:

> More informations in this regard ...
>
> - open file b5__hexa8_coarse.msh
> - in GMSH Tree click on Mesh --> Set order 2
> - Menue Tools --> Options --> Mesh --> Visibility --> activate Nodes
> - It seams we have got a second order mesh ?!
>
> - Menue Tools --> Visibility --> Numeric --> click on hide elements   
> (put in * before) --> click on show elements (put in 50 before)
> - screen is attached --> it really seams to be a hexa20 mesh
>
> - save as msh --> reload --> still a hexa20 mesh
> - save as unv --> reload --> no hexa20 mesh, it is a  hexa8 mesh
>
> Could it be hexa20 ist not supported in GMSH unv export ?? Could   
> someone else give more informations in this regard?
>
> GMSH 2.12.0
>
> kind regards bernd
>
>
>
> Zitat von Bernd Hahnebach <gmsh at b75.ch>:
>
>> Dear gmsh folks,
>>
>> attache a coarse hexa first order mesh. I'd like to get an second   
>> orde  hexa mesh out of this. I found the hight order tools can be   
>> used to  create the appropriate nodes for a second order hexa mesh.  
>>  But how do  I create elements out of the nodes.
>>
>> kind regards bernd
>>
>>
>
>
>
>



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