[Gmsh] Size fields question

Grégory LEGRAIN gregory.legrain at ec-nantes.fr
Fri Nov 21 10:34:36 CET 2014

Dear gmsh developers/users,
I am playing with size fields, and I experienced some strange results...

Consider the folllwing geo file :
lc = 1.e-2;

Point(1) = {0.0,0.0,0.0,lc};
Point(2) = {1,0.0,0.0,lc};
Point(3) = {1,1,0.0,lc};
Point(4) = {0,1,0.0,lc};
Line(1) = {4,3};
Line(2) = {3,2};
Line(3) = {2,1};
Line(4) = {1,4};
Line Loop(5) = {2,3,4,1};
Plane Surface(6) = {5};

Field[1] = MathEval;
Field[1].F = "0.1";
Background Field = 1;

As you can see, I should get a mesh with elements of size 0.1.

Unfortunately, I obtain a mesh with size 1.e-2 which was my initial 
characteristic length (see isoKO.png). Now, if I set lc=1. I get a 
correct mesh (see isoOK.png).

So my question is : did I miss something ? Is it normal that the size 
field is only taken into account when it is smaller than the initial 
characteristic length ? (i.e. no coarsening possible)

Best regards,

PS : I played also with anisotropic meshing, and in this case the metric 
is taken into account everywhere except on the boundaries.

Maître de Conférences - Assistant Professor
Responsable de l'option Modélisation et Simulation Mécanique (MSM)
GeM Institut de Recherche en Génie Civil et Mécanique - UMR CNRS 6183
Equipe structure et simulation

Ecole Centrale de Nantes
1 Rue de la Noe, 44321 Nantes, France
Email : gregory.legrain at ec-nantes.fr
Tel :
Fax :

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