[Gmsh] Re: Gmsh digest, Vol 1 #61 - 1 msg

[Jean-Francois Remacle <remacle@scorec.rpi.edu>]

> Hello,

Hello,

>
> I've been trying to use gmsh to construct 3D tetrahedral grids for our
> CFD work. I have run into considerable problems due to the creation of
> very flat tetrahedra when producing grids for complex geometries. Most
> of the
> flat tetrahedra are rather envelope-shaped. If you are interested, I
> can send a .geo file which will produce this effect.

The current version of the 3D tet mesh generator does not involve
any optimization steps. That means that slivers are often generated.
We have a procedure to improve mesh quality by edge and
face swapping but I just looked into the code and that part
is commented ;-) I guess there are bugs.

>
> This mucks up my calculations due to instabilities.
>

Yes, I know.

> I'm aware that the 3D grid generator is still experimental, but
> nevertheless I would like to ask if there exists a sort of
> workaround for this. Or is it foreseen that the problem will
> be tackled in the near future?

If you can find a tet mesh optimizator, that would help. I'm
going to work on that part and see what is wrong in my optimization
procedure.

>
> Otherwise I must say that the software looks very nice. I actually
> used it for a number of grids, but most of them have proven to be not
> really that useful due to this problem :-(.

Too bad, we're going to work on that.

JF

>
> TIA for any answer
>
> Thomas
>
>