[Gmsh] Different threshold fields around one attractor

[Christophe Geuzaine]

Moritz Nadler wrote:
> Christophe Geuzaine wrote:
> 
>> Hi Moritz - You take the minimum of all fields with Field[5]. So you 
>> will never see the 0.1 max char length from Field[4] (since you impose 
>> a smaller one, 0.005, outside Field[2].DistMax).
>>
>> Just change
>>
>> Field[2].LcMax = 0.005;
>>
>> into
>>
>> Field[2].LcMax = 0.1;
> 
> Thanks for your answer.
> 
> I tried the modification you told me already for myself (of course I 
> tried it again after your email) but it does not give the the result I 
> want. I produces a mesh density that looks like this:
> 
> 
> Mesh density
> ^
> | ----------------|
> |                 |
> |                 |
> |                 |
> |                 --------------
> |                               \
> |                                \
> |                                 \
> |                                  -------------
> |
> |                 ^ DistMin 1
> |                     ^ DistMax 1
> |                               ^ DistMin 2
> |                                  ^ DistMax 2
> _________________________________________________> Distance from attractor
> 
> 
> But what I want is this:
> 
> 
> Mesh density
> ^
> | ----------------
> |                 \
> |                  \
> |                   \
> |                    -----------
> |                               \
> |                                \
> |                                 \
> |                                  -------------
> |
> |                 ^ DistMin 1
> |                     ^ DistMax 1
> |                               ^ DistMin 2
> |                                  ^ DistMax 2
> _________________________________________________> Distance from attractor
> 



Indeed. I've added an option to the Threshold field so we can get this 
behaviour: cf. attached file.






> 
> Description of drawings:
> DistMin 1 and DistMax 1 corresponds to Field[2].DistMin and 
> Field[2].DistMax
> and DistMin 2 and DistMax 2 correponds to Field[4].DistMin and 
> Field[2].DistMax in my example file attached to this email.
> 
> 
> 
> After changing
> Field[2].LcMax = 0.005;
> to
> Field[2].LcMax = 0.1;
> the
> Field[2].DistMax = 0.2;
> command is ignored. Instead of a slow mesh density gradient from DistMin 
> of Field 2 to DistMax of Field 2 the mesh density almost instantly 
> changes from LcMin of Field 2 to LcMin of Field 4 at DistMin of Field 2.
> 
> 
> I only used the MinField because I want both threshold fields to be 
> used. If I use one of the threshold fields as a backround field the 
> other one will be totally ignored. I do not want that some mimimum 
> values of something are taken.
> All the values the 2 threshold fields should be taken as I stated them.
> 
> Does anybody know how I could produce my desired mesh?
> 
> 
> ------------------------------------------------------------------------
> 
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-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine
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