Hello !
Is there a way to render in wireframe mode in vray like with the standard scanline renderer ? I mean : rendering all mesh lines in color, even those hidden.
Yes. VrayEdgesTex map.
Just drop the map in the refract slot, and invert it. Also, set the IOR to 1.
The map doesn’t seem to work in the opacity slot.
Very useful cecofuli ! In addition I have the chance to understand italian 
Actually I only used VrayEdgesTex like indicated in the manual, but didn’t knew that when applied in the opacity channel it had that effect !
Grazie mille !