[Gmsh] Optimize tetrahedral meshes

[Yang Liu]

Hello,

I am a new user of Gmsh.  I am trying to use Gmsh to optimize
tetrahedral meshes.
The quality of my tet meshes are not bad but they have some slivers.
I loaded them into Gmsh (version. 2.4.2 / 2.4.3 in windows) and click
the button "optimize" / "optimize by netgen",
I also checked "Optimize quality of tetrahedra" ),
but there is no change of my mesh (I have exported the result and
compared to my original mesh) and tried different inputs.

So my questions are:
1. Is my operation wrong ?
2. Is it possible to adjust some parameters to control optimize function.

Thanks in advance,

Yang