[Gmsh] NODEDATA SECTION MISSING IN POS FILE

[Christophe Geuzaine]

On 16 Oct 2013, at 10:54, "Mandija, S." <S.Mandija at umcutrecht.nl> wrote:

> Hi,
> I am a PhD student. I started working with this program one month ago. 
> Before it was upgraded from my department, I was able to save post-processing data in a precise way.
> After opening a 3D meshed cylinder with a vector field in it (“filename.msh”), I was able to calculate the
> curl of this vector field (thanks to the gmsh plugin Curl) and save the result obtaining a *.pos file. In this
> file, after importing it in Matlab, there were a first section related to the node ($Nodes) so I was able to
> identify for each node the number of the node and the x-y-z coordinate value in four different columns,
> one section for the elements($Elements), and finally one section related to the node data($NodesData
> with the same size of the node section (same number of rows, each one for a different node, and the
> same number of columns, the first one identifying the node number and then three columns related to
> the x-y-z value of the curl of the vector field for that precise node).
> Now after upgrading the software, instead of having the final section related to “$NodeData” as before, I
> have a new section called $ElementNodeData with the same number of rows as the $Element section,
> and as columns, after two starting columns identifying the element number and type, I have three
> columns repeated four times since the mesh is made by tetrahedron as written in the online
> documentation.
> Since I really need the x-y-z value of the coordinate of each node and the x-y-z value of the curl of the
> vector field for each node, as I had before upgrading the software in the sections $Node and
> $NodeData, is there a way to obtain this information again? Is there a particular way to save the *.pos
> file so I can get this information again?
> 

Hi Stephano,

This behaviour was changed because many of the datasets created by the plugins are actually discontinuous by nature. The ElementNodeData can deal with such datasets, whereas NodeData cannot.

I've introduced an option in the latest nightly build (set "PostProcessing.ForceNodeData=1;" in your input file) to revert to the old behaviour. Be careful with it though: when used on a discontinuous dataset, it will simply save the data for one of the vertices ; no explicit smoothing is done. If you want to make the data continuous before saving it as "NodeData", you should first apply the "Smooth" plugin.

Hope this helps,

Christophe






> Hoping in a soon reply, I thank you all.
> Stefano
> 
> 
> 
>      
> Stefano Mandija M.Sc.|PhD Student|Department of Radiotherapy|University Medical Center Utrecht
> Heidelberglaan 100|3584 CX Utrecht|The Netherlands|Visiting address: Q04.4.302|Tel.: +31 88 7550285
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-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine