[Gmsh] Maillage d'un volume contenant une plaque 2D

[Christophe Geuzaine]

Gerard - I've added the following paragraph in the reference manual. I
hope it's easier to understand than my previous e-mail :-)

The mesh generation is performed in the same bottom-up flow as the
geometry creation: lines are discretized first; the mesh of the lines
is then used to mesh the surfaces; then the mesh of the surfaces is
used to mesh the volumes. In this process, the mesh of an entity is
only constrained by the mesh of its boundary(1). This automatically
assures the conformity of the mesh when, for example, two surfaces share
a common line. But this also implies that the discretization of an
"isolated" (N-1)-th entity inside an N-th dimensional entity does _not_
constrain the N-th dimensional mesh.

(1) For example, in three dimensions:

   * the triangles discretizing a surface will be forced to be faces of
     tetrahedra in the final 3D mesh only if the surface is part of the
     boundary of a volume;

   * the line elements discretizing a curve will be forced to be edges
     of tetrahedra in the final 3D mesh only if the curve is part of
     the boundary of a surface, itself part of the boundary of a volume;

   * a single node discretizing a point in the middle of a volume will
     be forced to be a vertex of one of the tetrahedra in the final 3D
     mesh only if this point is connected to a curve, itself part of
     the boundary of a surface, itself part of the boundary of a
     volume...

-- 
Christophe Geuzaine

Tel: (626) 395-4552    http://www.geuz.org
Fax: (626) 578-0124    mailto:geuzaine at acm.caltech.edu