[Gmsh] half of structure disappears

[Christophe Geuzaine]

> On 4 Mar 2018, at 17:46, Juan E. Sanchez <juan.e.sanchez at gmail.com> wrote:
> 
> Using the latest Mac OS snapshot, it is the same behavior.
> 
> 3 sections appear (air, gate, air)
> 
> I go into the visibility dialog, visualize both "gate" and "air", and the last "air" disappears.
> 

I think you are misunderstanding the definition of physical groups. Your boolean operations create 3 elementary volumes : left, center and right. You put the left one in the physical group "air" and the middle one in "gate". (Note that your boolean operations are unnecessarily complicated - you could just fragment the 2 boxes instead of doing a difference followed by a fragment.)

So if you select the 2 physical groups, indeed you hide the right volume...

> If I mesh before opening the visibility dialog, all 3 sections get meshed.
> 

Normal again: by default with the MSH2 format Gmsh only saves elements that belong to physical groupe.

> When I save the mesh, and then open the mesh file, one of the "air" sections is missing.
> 
> 
> Starting over:
> 
> If I open the visibility dialog, and select both physical groups, one of the "air" sections disappear.
> 
> Looking in the Elementary entities, it appears that there are 3 volumes.  It looks like one of the "air" sections did not get assigned to the Physical Group.
> 
> How do I ensure that both "air" sections get assigned to the same Physical Group?
> 

Physical Group ("air") = {3,4};

Christophe




> Regards,
> 
> Juan
> 
> 
> 
> 
> On 3/4/18 1:21 AM, Christophe Geuzaine wrote:
>> Dear Juan,
>> Not sure what you observe - your file seems to behave normally with the latest version. Can you try with the latest automated snapshot ?
>> Christophe
>>> On 3 Mar 2018, at 20:40, Juan E. Sanchez <juan.e.sanchez at gmail.com <mailto:juan.e.sanchez at gmail.com>> wrote:
>>> 
>>> Hello,
>>> 
>>> I am using the OpenCASCADE factory to create a fairly complicated structure.  In this simplified test case, I run into the issue where part of the structure disappears when the center of it is removed.
>>> 
>>> When GMSH opens the file, it looks correct.  Then when I start manipulating it in the Visibility dialog, half of the "air" volume disappears.
>>> 
>>> When 3d meshing half of the "air" volume is also missing.
>>> 
>>> When I reopen the saved mesh, half the "air" volume is also missing.
>>> 
>>> Could someone please take a look?
>>> 
>>> 
>>> Regards,
>>> 
>>> Juan Sanchez
>>> <test.geo>_______________________________________________
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>> —
>> Prof. Christophe Geuzaine
>> University of Liege, Electrical Engineering and Computer Science
>> http://www.montefiore.ulg.ac.be/~geuzaine
>> Free software: http://gmsh.info | http://getdp.info | http://onelab.info
> 

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

Free software: http://gmsh.info | http://getdp.info | http://onelab.info

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