[Gmsh] Volume has changed error

[Christophe Geuzaine]

Martin Lüthi wrote:
> Hi
> 
> What does this error message mean:
> 
> Warning : Volume has changed (312915->137478) ?
> 
> Apparently something bad happens here, but why, and how could I
> correct it? I am using gmsh in batch mode like this (geo.geo is
> attached below)
> 
> gmsh geo.geo -2 -clscale 5 -o remeshed.msh
> 
> If I use a different element size
> 
> gmsh geo.geo -2 -clscale 6 -o remeshed.msh
>                         ***
> 
> then a new mesh is generated. However, with -clscale 5.2 I get
> 
> Info    : Elimination (1 swaps)
> Info    : Swapping (1 missing edges)
> 
> If I use the same mesh in interactive mode with different settings for
> clscale (in the options box) weird things happen (sometimes the mesh
> is displayed rotated) or the program simply hangs.
> 

When this happens with the old 2D algorithm (Isotropic), you should try 
again with a smaller random perturbation factor. Otherwise use 2D 
algo=Triangle. (You can change these options in 
Tools->Options->Mesh->General)

Christophe

-- 
Christophe Geuzaine
Applied and Computational Mathematics, Caltech
geuzaine at acm.caltech.edu - http://geuz.org