[Gmsh] Transparency

[Christophe Geuzaine]

Nicolas TARDIEU wrote:
> Hi!
> 
> I have several questions about transparency :
> 
> - when I was a kid, I remember that Gmsh allowed GUI view-per-view
> treatment of transparency... Is it still possible? How to make a view
> become transparent?

Hello Nicolas - In the GUI, go the view colormap option and press A (or 
Ctrl+A) to change the alpha channel and/or P (or Ctrl+P) to modify its 
curvature. You can also directly draw the alpha channel by pressing Ctrl 
while dragging the mouse.

In a script, you can use 4 components in colormap colors (the 4th is the
alpha value), and/or use the View.ColormapAlpha and
View.ColormapAlphaPower options.


> - would it be complicated to introduce transparency in mesh display?
> Are you interested in it?

It would be complicated, because we draw the meshes per surface (and not
"all at once"), which makes global sorting problematic... At the moment,
I would thus recommend using the post-processing module to draw 
transparent meshes (by using the "Show element edges" option).

Take care,

Christophe

-- 
Christophe Geuzaine
Applied and Computational Mathematics, Caltech
geuzaine at acm.caltech.edu - http://geuz.org