so I am having an issue understanding why you right multiply for current frame rotation vs left multiply for fixed frame.
Let us say you want to: Rotate about x, then Rotate about current y, then rotate about newer z.
So we have Rx, then Ry'(prime because it is the new y, not original) and then Rz''
It makes sense that it should be like this
You take a vector P and you rotate it about x to create a new vector p'. That is p'=Rxp. Then you take this new vector (p') and rotate it about z to create p'', that is: p''=Rz''p' = Rz''(Rxp)
That means that you left multiply when you are doing successive rotation about the current frame. However it is the opposite, and I can't understand why...