> On 31 Jan 2019, at 10:26, Alessandro Vicini <alessandro.vic...@sitael.com> 
> wrote:
> 
> 
> Great, thank you. Could you clarify what are the 9 values that you associate 
> with the element and with each node?

the 9 tensor components, per row

> 
> A.
> 
> 
> -----Messaggio originale-----
> Da: Christophe Geuzaine [mailto:cgeuza...@uliege.be] 
> Inviato: giovedì 31 gennaio 2019 09:46
> A: Alessandro Vicini
> Cc: gmsh@onelab.info
> Oggetto: Re: [Gmsh] Post-processing stress field
> 
> 
> 
>> On 31 Jan 2019, at 09:40, Alessandro Vicini <alessandro.vic...@sitael.com> 
>> wrote:
>> 
>> 
>> I would be grateful if you could post a similar MSH2 example for a 
>> tetrahedron grid, with 1 data field assigned on nodes and another one 
>> assigned on cell centers...
>> 
> 
> Here we go:
> 
> $MeshFormat
> 2.0 0 8
> $EndMeshFormat
> $Nodes
> 4
> 1 0.0 0.0 0.0
> 2 0.1 0.0 0.0
> 3 0.1 0.1 0.0
> 4 0.0 0.0 0.1
> $EndNodes
> $Elements
> 1
> 1000 4  2 6 100  1 2 3 4
> $EndElements
> $ElementData
> 1
> "stress field per element"
> 1
> 0.
> 3
> 0
> 9
> 1
> 1000  1 0 0 0 2 0 0 0 3
> $EndElementData
> $NodeData
> 1
> "stress field per node"
> 1
> 0.
> 3
> 0
> 9
> 4
> 1  1 0 0 0 2 0 0 0 3
> 2  1 0.1 0.1 0.1 2 0.1 0.1 0.1 3
> 3  1 0.2 0.2 0.2 2 0.2 0.2 0.2 3
> 4  1 0.3 0.3 0.3 2 0.3 0.3 0.3 3
> $EndNodeData
> 
> 
> 
>> A.
>> 
>> 
>> -----Messaggio originale-----
>> Da: gmsh [mailto:gmsh-boun...@ace20.montefiore.ulg.ac.be] Per conto di 
>> Christophe Geuzaine
>> Inviato: giovedì 31 gennaio 2019 09:37
>> A: Max Orok
>> Cc: gmsh@onelab.info; Gaetano Camarda
>> Oggetto: Re: [Gmsh] Post-processing stress field
>> 
>> 
>> 
>>> 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
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> gmsh mailing list
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>>> 
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>>> 
>>> 
>>> --
>>> Max Orok
>>> Contractor
>>> 
>>> https://urlsand.esvalabs.com/?u=http%3A%2F%2Fwww.mevex.com&e=9895bfa0
>>> &
>>> h=21dbbfec&f=y&p=y
>>> 
>>> 
>>> 
>>> 
>>> --
>>> Max Orok
>>> Contractor
>>> 
>>> https://urlsand.esvalabs.com/?u=http%3A%2F%2Fwww.mevex.com&e=9895bfa0
>>> &
>>> h=21dbbfec&f=y&p=y
>>> 
>>> 
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>> 
>> —
>> Prof. Christophe Geuzaine
>> University of Liege, Electrical Engineering and Computer Science  
>> https://urlsand.esvalabs.com/?u=http%3A%2F%2Fwww.montefiore.ulg.ac.be%
>> 2F~geuzaine&e=9895bfa0&h=408b631c&f=y&p=y
>> 
>> 
>> 
>> 
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>> istinfo%2Fgmsh&e=9895bfa0&h=91a6eddd&f=y&p=y
> 
> —
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science  
> https://urlsand.esvalabs.com/?u=http%3A%2F%2Fwww.montefiore.ulg.ac.be%2F~geuzaine&e=9895bfa0&h=408b631c&f=y&p=y

— 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine




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