I do not understand clearly the gl coordinates used to draw the text of axis. Because then i would try to integrate 3D axis to represent rotations of the world but the lines i draw aren’t correctly shown.
Hi Alexandre,
You’re not the only one; I usually test every possible option until I find one that does the right thing 
There’s an issue listed on GitHub where we discuss the prospect of something that resembles what I think you’re describing; it might be worth cross-referencing that with your own thoughts.
Initially I’d suggest that the code used to draw the axis labels is the wrong reference to be using. Those require additional explicit transformation from 3D scanner space to the 2D viewing window, in order to provide pixel locations to the font renderer. Visualisation of the axes themselves are probably more likely to be native to the 3D space, in which case you typically instead rely on the transformation matrix within the GL vertex shader and subsequent rasterisation.
Rob