[Gmsh] ... electric field lines ...

[Tammo Heeren]

Maybe I am not getting it, but

if you have the electric field vector you can calculate the magnitude of the 
electric field with the extract plugin. This will generate a new view for you. 
If you then use [options][range][iso-values] for this view, you will get electric 
field lines.

Tammo

On 5 Oct 2006 at 18:57, Christophe Geuzaine wrote:

> Matt Koch wrote:
> > Hi All,
> > 
> > this seems to be a simple matter of solving the following equations for 
> > F = (Fx,Fy,Fz) as the vector (yeah right, NOTHING is EVER simple):
> > 
> > dx/ds = Fx/|F|
> > dy/ds = Fy/|F|
> > dz/ds = Fz/|F|
> > 
> > with |F| = sqrt(Fx^2 + Fy^2 + Fz^2)
> > 
> > Even a dumb Runge-Kutta approach could probably do. I might could give 
> 
> Isn't this pretty much what we do in Plugin(StreamLines)? There we
> solve dX(t)/dt = V, with X(0) chosen as a bunch of points in space and 
> V(x,y,z) interpolated from the vector view.
> 
> > it a try, but I'd need to know how to write plugins (how to 
> > programmatically access fields calculated by GetDP, how to 
> > programmatically draw in GMsh, and such), and perhaps get some feedback 
> > from y'all on how long it might take to write a "typical" plugin? Would 
> > some sort of Runge-Kutta driver or other ODE solver be accessible to a 
> > plugin, or would that have to be developed from scratch, or pulled in 
> > from GSL, for example?
> 
> Have a look at Plugin/StreamLines.cpp in the Gmsh source code: you'll
> see that it's actually pretty simple to write a plugin.
> 
> 
> 
> > 
> > Thanks,
> > 
> > Matt Koch
> > 
> > 
> > Christophe Geuzaine wrote:
> > 
> >> Matt Koch wrote:
> >>
> >>> Hello there!
> >>>
> >>> what a wonderful program GMsh is! It takes a little while to get used 
> >>> to its GUI, but once you get the hang of it, it is extremely useful 
> >>> and intuitive! However, one thing I have not been able to figure out 
> >>> yet is how to make electric field lines from an electric field vector 
> >>> solution. I looked into the StreamLines PlugIn, but that seems to 
> >>> only work off of a velocity field. Any thoughts?
> >>
> >>
> >> Maybe this could be a good idea for a new plugin?
> >>
> >>
> >>>
> >>> Thanks,
> >>>
> >>> Matt Koch
> >>> mattkoch at scitex.us
> >>> www.scitex.us
> >>> _______________________________________________
> >>> gmsh mailing list
> >>> gmsh at geuz.org
> >>> http://www.geuz.org/mailman/listinfo/gmsh
> >>>
> >>
> >>
> > 
> 
> 
> -- 
> Christophe Geuzaine
> Assistant Professor, Case Western Reserve University, Mathematics
> http://www.case.edu/artsci/math/geuzaine
> 
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