Hello everyone 
To give you some insight into my problem, I’m currently working on my first Facial Rig and for the eyelids I was trying to follow this tutorial to align my joint along a curve :
At first all is working well, my main axis [ X ] points along the tangent of the curve as I want.
But when I try to stabilize the rotation with a second axis, again just like in the video, I have some weird behavior that I can’t comprehend.
In the video, he stabilize the [ Y ] axis, but in my case I want [ Z ] to be the secondary axis.
By following his instructions, I plug the vector I want to use in the In 30, In 31 and In 32 of the 4 by 4 matrix (which is supposed to be for the [ Z ] axis if I’ve understood well) but nothing happens.
If I do the same thing as he does and try to orient the [ Y ] axis, the joint orient itself like I would want but the [ Y ] axis is where I’d like the [ Z ] to be.
At first I thought that it could be a rotate order problem, so I tried to go from XYZ to XZY and others but there the orientation is not at all what I’d like.
It’s my first time using a four by four matrix so it’s pretty confusing for me ! I really hope someone out there as an idea of what’s going on and that I’ve been clear in my explanations
Have a nice day all !