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samy902 July 19, 2013 05:01

Refinement Region
Hello everyone,

i am trying to generate the mesh with snappyHexMesh but when i want to visualise it on paraView i can't see the refinement region that i have specified around the object. I feel that it has to do with the physical memory of my computer but, right now, i want to hope to another explanation.

Thanks in advance.

colinB July 19, 2013 05:38

Hi samy902,

welcome to the forum.

Before answering your question, please be advised that there are
some forum-rules which make life of the users little bit easier, so
one of them is to post questions in the proper subforum, to
ease the search for other users.

Since you mentioned snappyHexMesh in your post, this would have been
the proper channel for you.

Another rule is that one who asks the questions tries to provide
as much information as possible to give the other users a clear picture
of what is wrong.
For further hints have a look here:

Now looking at your question you will quickly notice that when trying to
answer it, every outstanding person will have to guess for
we don't know:

- what looks your snappyHexMeshDict like
- don't have a picture of your geometry pointing out the problem
- don't have a log file of the meshing process which eventually contains
- evtl. the checkMesh result gives also a hint (what I don't expect in
this particular case, but you never know since its a meshing problem)

Everything I would tell you know would be a wild guess so I'll leave it and
wait for more information ;-)

I hope I could contribute


samy902 July 19, 2013 07:33

Refinement region
2 Attachment(s)
Hi ColinB,

i am really sorry, you are absoluterly right. I have added a pdf file to point out my problem and a zip file that contains the snappy.log and snappyHexMeshDict. I hope that helps.

Thanks again.

colinB July 19, 2013 08:27

Hey samy902,

the only obvious thing I could find was



            mode inside;
            levels ((1E15 1));

That I use the scientific expression with a high
number instead of 1.0 which you used
Note: that the first number in the round brackets is actually
irrelevant and it is just a dummy value

But you mentioned that you have troubles with your memory.
I don't think this is the problem for otherwise the calculation would crash

However you are hitting the maxGlobalCell value (you specified
2 Million and with refinement level 5 of 6 you have already 3.8 Mio.)
Maybe this is the reason why he refuses to refine the box.

Maybe with these two hints you can start trying to solve your

samy902 July 19, 2013 08:38

Refinement region
I fixed it. As you mentioned cause of the fact that i am hitting maxCells it can not refine anymore. I tried the a less refined case in BlockMesh ( simpleGrading (1 1 1) ) than the one before ( simpleGrading (1 1 15) ) and it totally solved my problem. I will try your proposal as well to check if i can decrease the refinement level and keep the higher simpleGrading. Thanks again for your help colinB.


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