> On 30 Jan 2019, at 23:58, Max Orok <mo...@mevex.com> wrote:
> 
> Yes, the stresses belong in the $ElementData section for sure. 
> I think to correctly display it, you'll need to create rows of element data 
> with 10 entries - 1 for the element number and 9 for the stress tensor values:
> 
> 1 sigx sigxy sigxz sigxy sigy sigyz sigxz sigyz sigz 
> 
> I don't know if copying and pasting this pattern in ElementData will work 
> without some tweaks...

That's correct. Here is a simple MSH2 example with 2 quads, with values [1 0 0, 
2 0 0, 3 0 0] and [1 0.1 0.1, 0.1 2 0.1, 0.1 0.1 3]:

$MeshFormat
2.0 0 8
$EndMeshFormat
$Nodes
6
1 0.0 0.0 0.0
2 0.1 0.0 0.0
3 0.1 0.3 0.0
4 0.0 0.3 0.0
5 0.0 0.15 0.0
6 0.1 0.15 0.0
$EndNodes
$Elements
2
1000 3  2 6 100  1 2 6 5
1001 3  2 6 100  5 6 3 4
$EndElements
$ElementData
1
"stress field per element"
1
0.
3
0
9
2
1000  1 0 0 0 2 0 0 0 3
1001  1 0.1 0.1 0.1 2 0.1 0.1 0.1 3
$EndElementData

PS: the next release will improve the computation of the min/max for tensor 
fields. (Currently the min/max is computed using the default representation for 
tensors, i.e. Von-Mises. The next release will take the tensor visualization 
mode into account when explicitly requesting the calculation of min/max.)

Christophe


> (there is an InterpolationScheme section that I don't quite understand). If 
> it were me, I would add the data using the gmsh API and it will handle the 
> output format how it likes. 
> 
> Sincerely,
> Max
> 
> 
> On Wed, Jan 30, 2019 at 2:42 PM Gaetano Camarda <gaetano...@live.it> wrote:
> Thanks for your help, but I think I have not understood well. 
> I have a mesh all brick (8 nodes) and my stress field matrix is composed this 
> way:
> 1 sigx sigy sigz sigxy sigyz sigxz
>    ...     ....    .....    .....    ......    .....
> 
> In each row is express the stress state of the element, I think I have to 
> copy this matrix into .msh file as $ElementData, but I do not unsterstand 
> well the input format, is that right this way? 
> 
> 
> Outlook per iOS
> Da: Max Orok <mo...@mevex.com>
> Inviato: martedì, gennaio 29, 2019 7:14 PM
> A: Gaetano Camarda
> Cc: gmsh@onelab.info
> Oggetto: Re: [Gmsh] Post-processing stress field
>  
> Hello Gaetano, 
> 
> Here is a short program to plot 3x3 tensor data using the C++ gmsh API (it 
> shouldn't be too hard to port to Python or Julia if you're more comfortable 
> there). It only plots data for one element, but can be extended for your case.
> 
> The "addModelData" call is expecting a vector of vectors with 9 entries each 
> for this case.
> I think the vector ordering corresponding to the matrix is like this: 
> [elt11, elt12, elt13, elt21, elt22, ...] 
> 
> I assume the stress matrix is symmetric and so only has 6 unique entries.
> Therefore your vector entries will look like [x xy xz xy y yz xz yz z]
> The tricky part will be importing the data in a sensible way.  
> 
> Perhaps you could parse a CSV using python and add entries to the data vector 
> in a loop?
> Please find attached the program as well as example input mesh and output 
> mesh files.
> 
> 
> 
> <image.png>
> 
> Sincerely,
> Max
> 
> On Tue, Jan 29, 2019 at 11:24 AM Gaetano Camarda <gaetano...@live.it> wrote:
> Hello everyone,
> 
> I’m having some difficult on post processing a mesh I created.
> 
> I create a mesh on Gmsh all Hexa (so a brick with 8 nodes), i use this mesh 
> and import it on Matlab,
> 
> there i run some analisys and find the stress matrix:
> 
> [sigx sigy sigz sigxy sigyz sigxz]
> 
> …..    …..    …..   …..    …..    …..
> 
>  
> 
> Now I would like to visualize the stress field on Gmsh, but I do not find any 
> way to do so, I can export the matrix,
> 
> I tried to generete a *.pos file, but I didn’t find a solution.
> 
>  
> 
> Inviato da Posta per Windows 10
> 
>  
> 
> _______________________________________________
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> 
> 
> -- 
> Max Orok
> Contractor
> www.mevex.com
> 
> 
> 
> 
> -- 
> Max Orok
> Contractor
> www.mevex.com
> 
> 
> _______________________________________________
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— 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine




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