[Gmsh] Normals

[Nacho Andres de la Fuente]

Dear all,

I am using gmsh in combination with getdp and I am a newbie so I would
like to ask for some helpful advices. I have to include a discontinuity
(i.e. passing from conductivity_1 to conductivity_2) in getdp and
therefore I need the normals defined outwards for all the surfaces to
impose the appropriate boundary conditions. 

I have done two things in gmsh:
1) define the inner surface and the outer surface different (i.e. with
different geometrical elements) corresponding to the same geometrical
location => gmsh gets crazy when meshing since it finds out that the
elements are adjacent.
2) create an inner volume giving it the right normals and the outer
volume being the first one with the gap of the second => the problem
with the normals appear: the outwards direction for the inner volume is
right but for the outer volume gets the inwards direction (opposite to
what I would need for the boundary condition for getdp)

I am certainly doing something wrong and sure some of you have the right
answer for this.
 
Many thanks in advance,

Nacho