License

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payoubi
Posts: 25
Joined: Tue Nov 15, 2016 2:50 am

License

Postby payoubi » Tue Nov 15, 2016 2:52 am

I am wondering is there any difference between 1 month free license and the regular license that we can buy in terms of number of elements and nodes?

I am trying to model something with more than 2M quadilateral elements but GiD seems to have problem with this.

Your time is appreci
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escolano
Posts: 1568
Joined: Thu Sep 18, 2014 3:31 pm

Re: License

Postby escolano » Tue Nov 15, 2016 6:07 pm

No, there is no difference in terms of number of elements and nodes using a temporary or permantent licence.

If the process require more than 2GB to generate your meshes, then you must use a x64 GiD version (x32 platforms can't handle more than 4GB of memory, and usually crash when reaching 2GB)

If do you want can attach a zip with the model to test it.
payoubi
Posts: 25
Joined: Tue Nov 15, 2016 2:50 am

Re: License

Postby payoubi » Wed Nov 16, 2016 7:54 am

Consider a model like this which I want to mesh it for element size of 0.5 m. It will go for order of several millions. But, GiD cannot handle it and it crashes after 1M elements.


I computer is 64bit with 40 cores and 256GB RAM.
I am pretty sure it has nothing to do with computer and OS.


Thanks for your time.
Attachments
1.gid.zip
(5.81 KiB) Downloaded 121 times
1.png
1.png (3.09 KiB) Viewed 1980 times
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escolano
Posts: 1568
Joined: Thu Sep 18, 2014 3:31 pm

Re: License

Postby escolano » Wed Nov 16, 2016 3:47 pm

Some comments:
1) your model has dimensions 30000x2000
using mesh size=0.5 units, if it was a uniform mesh with all cuadrilaterals of this size
30000x2000/(0.5^2)=240000000 quadrilaterals
240 millions of elements is probably too much!!
(and the mesh won't be uniform, you probably will potentially obtain much more elements)

2) On other hand, seems that there are other precision problems meshing your example with small sizes,
Arc lines are more unstable numerically than NURBS (a small change in values of its parameters become a big change in the shape)
you convert the lines to NURBS with
Geometry->Edit->Convert to NURBS->Lines

And they continue having problems meshing some surfaces (we must study it deeply...), you can try to do some modifications:
in general a good strategy is to divide the problematic part in two smaller problems, until isolate the problem.
Then you could try other things to be able to mesh, like assign mesh sizes to some entities, modify or rebuild some entities, try to create untrimmed surfaces instead of planar trimmed surfaces, assign structured mesh to some 'four sides' surfaces, etc.
I recommend to test it first meshing with triangles, when it works try with quadrilaterals (if it fail with triangles it will fail with quadrilaterals)

I attach a modified model '2.gid' with this kind of modifications, and the lower surfaces (Layer1) meshed structured (approx size=5), and the rest unstructured with general size=5. It generates about 3 Milions of quadrilerals (the mesh is not included to avoid a big file)
2.zip
(40.52 KiB) Downloaded 107 times


3) Nowadays in GiD each surface should be meshed by a single processor, to make more profit of your multiple 40 processors you can modify the geometry and divide the surfaces. Then each surface could be easier (faster and spend less memory) to be meshed, because there are few elements to find its collisions, and also could be meshed in parallel each one in a processor.
Note: to enable parallel meshin of surfaces and volumes must set more than a thread in Utilities->Preferences... General->Other - Number of threads to use. You can set for example here this number equal to your amout of CPUS=40
payoubi
Posts: 25
Joined: Tue Nov 15, 2016 2:50 am

Re: License

Postby payoubi » Thu Nov 17, 2016 5:12 am

Thank you so much.

Bests

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