[Gmsh] Mesh with a background mesh

[Christophe Geuzaine]

Marc Duflot wrote:
> Hello,
> 
> I have some problems when I try to mesh a geometry with a hole, with a
> background mesh for the elements size.
> 
> I attach some files that show the problems. cylpart.geo is the geometry
> I use to make a first mesh cylpart.msh. OptimalSize.pos defines the
> wished element sizes on this first mesh. Then, I try to mesh the
> geometry with
> 
>    gmsh -2 -bgm OptimalSize.pos -o cylpart2.msh cylpart.geo
> 
> (only surface mesh for now). It fails with a lot a warnings:
> 
>    Warning : Characteristic length <= 0: setting to 1.0
> 
> It seems that some points fall outside the first mesh.
> 
> If I add a big tet at the end of OptimalSize.pos that covers the whole
> geometry
> 
>    SS (-100,-100,-100,500,-100,-100,-100,500,-100,-100,-100,500)
>       {1.0,1.0,1.0,1.0};
> 
> then it succeeds but the resulting mesh is ugly because for sometimes
> the small size of OptimalSize is used and sometimes the default value
> 1.0 is used.
> 
> Any hints?
> 

Hello Marc - Tomorrow's cvs snapshot should be much better about this
(and a lot faster, too). Here is a slightly modified version of your
test file: I have removed the big tet because in the new version, if
there is a big tet that englobes the smaller ones, the smaller ones will
never get picked up by the search algorithm.

Christophe


> Marc
> 
> 

-- 
Christophe Geuzaine
Assistant Professor, Case Western Reserve University, Mathematics
http://www.case.edu/artsci/math/geuzaine
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