The mentioned article does have some, what I would call massive mistakes in it..it seems to me that the writer has had it explained to him and he didn’t completely understand it.
I think, part of the confusion is that we also have “X”, “Y”, “Z” and “W” in “Axis Angle Rotation”
That is indeed very confusing! Those are completely different things!
Unfortunately, I don’t understand the rig and what exactly needs to be driven by what…and using Local Space doesn’t make it easier for me.
