[Gmsh] Coloring the mesh + symmetry question

[David Colignon]

Guido Valerio wrote:

> Dear all,
> 
> i'm new to Gmsh and i'm trying to mesh a simple rectangle with a wire 
> attached to it, and then writing everything in a ".unv" file (i'm 
> attaching both the .geo, .msh and .unv file). I have problems in 
> performing some operations.
> 
> 1) Is it possible to require that two opposite sides of the rectangle be 
> meshed with the same nodes (apart a translation?). For example, side x=0 
> has nodes (0, y_n, 0), side x=a has nodes (a, y_n, 0). If, so, is it 
> possible to require this for two opposite faces of a solid, e.g. side 
> x=0 has nodes (0, y_n, z_m), side x=a has nodes (a, y_n, z_m)?

Hi Guido,

yes, it is very simple with extrusion (Extrude and Transfinite commands). See 
http://www.geuz.org/gmsh/doc/texinfo/gmsh-full.html#SEC40  and
http://www.geuz.org/gmsh/doc/texinfo/gmsh-full.html#SEC45

and also the three first tutorials: http://www.geuz.org/gmsh/doc/texinfo/gmsh-full.html#SEC64


> 
> 2) Also, is it possible to require a symmetric mesh with respect to a 
> point, one or more lines, or one or more surfaces (on a symmetric 
> object, of course)?

It depends on your geometry, but it should be doable with extruded meshes.

> 
> 3) Is it possible to set different colors on different elements of the 
> mesh? 

No. You can set the color of different parts of the mesh, but not on a per element basis.

http://www.geuz.org/gmsh/doc/texinfo/gmsh-full.html#SEC46

Color color-expression { Point | Line | Surface | Volume { expression-list }; ... }
     Sets the mesh color of the entities in expression-list to color-expression.

Cheers,

Dave

-- 
David Colignon, Ph.D.
Collaborateur Logistique du F.R.S.-FNRS
CÉCI - Consortium des Équipements de Calcul Intensif
ACE - Applied & Computational Electromagnetics
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Université de Liège
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I need to use color A for all the 2-node lines, color B for all
> the triangles not touching side x=0 of the rectangle, color C for all 
> the triangles touching side x=0 of the rectangle. In doing this, I have 
> two problems:
> 
> 3a) I cannot assign different colors to the different triangles, and 
> 3b) I cannot save the colors of the elements in the ".unv" file. I get 
> always a '7' in the place of the color for all the elements. I would 
> need to change that number.
> 
> Sorry if some of the points are trivial, or too weird to have them 
> implemented.
> 
> 
> Thank you very much for the attention and congratulation for designing 
> such a useful and easy-to-use software.
> 
> Guido
> 
> 
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