The assignment I'm working on is asking to perform a rotation and find the image $Q$ of the point
P = (1, 2, -1) after a $45$ degree $y$-roll. I was under the impression that a roll was on the $z$-axis; which is where I'm confused.
I'm trying to set up the problem like such (from WikiPedia):
But I'm lost as to translate the 3 points into a matrix. Is this correct? The way I'm trying to visualize it as below without the translation.