[Gmsh] Different threshold fields around one attractor

[Moritz Nadler]

Hallo,

I want to have 2 threshold fields around one attractor so I get get
one area with very fine mesh directly around the attractor point
from the attractor point to the DistMin value of the inner threshold field.
Then a linear mesh density gradient from the DistMin to DistMax value of the 
first threshold field where at DistMax the mesh density of the second threshold 
field is reached and stays until the DistMin value of the second threshold is 
reached
And then a linear density gradient from DistMin to DistMax of the second 
threshold field.

What I thourght is the obvous way to do this did not work:

Field[1] = Attractor;
Field[1].NodesList = {5};

Field[2] = Threshold;
Field[2].IField = 1;
Field[2].LcMin = 0.001;
Field[2].LcMax = 0.005;
Field[2].DistMin = 0.05;
Field[2].DistMax = 0.2;

Field[3] = Attractor;
Field[3].NodesList = {5};

Field[4] = Threshold;
Field[4].IField = 3;
Field[4].LcMin = 0.005;
Field[4].LcMax = 0.1;
Field[4].DistMin = 0.3;
Field[4].DistMax = 0.5;

Field[5] = Min;
Field[5].FieldsList = {2,4};

Background Field = 5;

Because only when both threshold fields have the same LcMax value I get 2 
circles around the attractor point. If I use the above posted values the general 
mesh denstiy is way to high and there is only one circle in the middle.

Does anybody know what the right gmsh semantics for my problem are?


kind regards


Moritz
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