[Getdp] Magnetic Field Lines From 3D Magnetic Field?

[Alain]

Dear Users:
In magnetostatic 2D examples, it is easy to look at the magnetic lines 
which lines up quite nicely with the magnetic field vector simply by 
setting Iso-values as graphic output on the "a scalar potential" view.
    However, for 3D magnetic field, as I mentioned before, it is not so 
easy. First, the "3D scalar potential" does not seem to be as accurate 
as in the 2D case and cannot be used. Second, using only the 3D magnetic 
field vector as base view, it does not seem to be possible to ever see 
these field lines in any 2D plane extraction schemes e.g.   cut plane , 
cut grid , extract ,skin  etc. The only Iso-lines views are always 
perpendicular to the field lines.

    What is the proper way to do this? This may be a Gmsh question but 
maybe I am not using the proper field solution in Getdp.
     I would really like to be able to see these lines.
     Maybe  it is not possible to do. You can use the "ring_magnet.pro" 
to see what I mean.
Thanks,
Alain Martin