[Gmsh] transparency

[Andre Antunes]

Hi

Would it be possible to make a specific physical group or elementary entity semi-transparent? 
That would be a very welcome addition. 

I read a thread from 5 years ago that suggested saving the mesh to a .pos file and "save geometry tags in the view and enables the alpha channel there", but I can't see how this is done. 

For example, I created the simplest of .pos files, with 2 hexahedra, named exp.pos:
View "1" {SH(0,0,0,1,0,0,1,0,1,0,0,1,0,1,0,1,1,0,1,1,1,0,1,1){1,1,1,1,1,1,1,1};};
View "2" {SH(0,0,1,1,0,1,1,0,2,0,0,2,0,1,1,1,1,1,1,1,2,0,1,2){2,2,2,2,2,2,2,2};};


and a .geo file
Include "exp.pos";
View[1].Color.Hexahedra = {0,0,0,100};


I was hoping this would set the transparency of hexahedra in view 1 in the alpha channel, but it does not.

Would anyone know how?

Best regards, 
Andre