[Gmsh] 3D volume as tetrahedra only

Keith Sloan keith at sloan-home.co.uk
Mon Jun 8 08:58:38 CEST 2020

I am new to Gmsh and trying to reproduce the following but still seeing 
triangles on the surface.

Can I check that when it mentions sphere demo it is talking about 

// merge a surface mesh (any format will work: .msh, .unv, etc.)

Merge "sphere-surf.stl";

// add a geometrical volume

Surface Loop(1) = {1};
Volume(1) = {1};
Physical Volume('tets') = {2};

// use this to force a coarse mesh inside
//Mesh.CharacteristicLengthExtendFromBoundary = 0;
//Mesh.CharacteristicLengthMax = 0.5;

I have also tried
Physical Volume('tets') = {1};

Previous discussion

Mark Starnes mark.starnes at fttech.co.uk
Tue May 1 10:42:09 CEST 2012
Previous message: [Gmsh] 3D volume as tetrahedra only
Next message: [Gmsh] 3D electrostatic BEM solver
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hi Bartek,

Yes:  use a Physical Group definition in your .geo
file, like this:

Physical Volume('tets') = {2};

where `2' in this case would be the volume number
assigned to your tetrahedra and 'tets' is a name I
made up.

Adding a `Physical Group' definition results in
only the groups specified as being physical being

Search for, `Physical' in the manual:


Best regards,


On Tue, May 01, 2012 at 09:15:31AM +0200, Bartek Grychtol wrote:
 > Hi,
 > I'm new to gmsh, just seeing if it can do what I need.
 > I have a surface mesh in an stl file. I need to create a nice
 > tetrahedral volume mesh,
 > but without changing anything on the surface.
 > The sphere demo does exactly that.
 > However, the generated .msh file contains both triangles (for the
 > surface) and
 > tetrahedra (for the volume inside).
 > Is there a way (a command or file format) to have the complete mesh
 > represented as tetrahedra only?
 > Best wishes,
 > Bartek
 > _______________________________________________
 > gmsh mailing list
 > gmsh at geuz.org
 > http://www.geuz.org/mailman/listinfo/gmsh

Dr. Mark Starnes
Principal Physicist
FT Technologies
Church Lane
TW11 8PA

web:  www.fttech.co.uk
DDI:  0208 614 2730

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://onelab.info/pipermail/gmsh/attachments/20200608/32d83d28/attachment.html>

More information about the gmsh mailing list