[Gmsh] how to cut a 3D mesh?

[Christophe Geuzaine]

Cécile DAGES wrote:
> Hi !
> 
> I would like to know if it is possible to truncate a 3D mesh  of a cube 
> for example by a plane and to save the result as a new 3Dmesh (tetraedric).
> 

Gmsh can only cut or clip the mesh for display---not save the modified mesh.

PS: When you say "truncate a 3D mesh", do you mean "keep the tetrahedra" 
that are entirely on one side of a plane"? Or do you mean "keep the 
tetrahedra entirely on one side of a plane AND re-triangulate
the intersecting tetrahedra"?

The former would be very easy to add: it's just a matter of saving a 
reduced number of elements. The latter is more complicated, but already 
available in Gmsh in the post-processing plugins (Plugin(CutPlane), 
Plugin(CutSphere), Plugin(CutMap), with ExtractVolume set to -1 or +1). 
However these plugins create post-processing views (not meshes), so you 
would have to extract the mesh from the post-processing views.

Christophe



> Best Regards
> 
> Cécile
> 


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