Cutshots' and Straightline’s methods to determine the aiming line differ in two ways.
Straightline uses a step Cutshots doesn’t: Straightline uses the midpoint between object and cue balls while Cutshots does not. Likewise, Cutshots uses a step Straightline doesn’t: CueShot uses the concept of equal and opposite areas of overlap between the object and cue balls at contact to determine the aiming line while Straightline recognizes that geometry but it is not needed to determine the aiming line (the line before parallel adjustment).
Straightline and CutShots’ methods determine the aiming line by first finding the object-ball contact point. CutShots’ method then has the player looking at the object-ball contact point and noting how there are equal areas from the contact point to ball edge on each side of the contact point.
CutShots then has the player shifting his view to now looking at the object-ball contact point from behind the cue ball. With this new view, CutShots notes how the visible area on one side of the object-ball contact point now has shrunk. Utilizing the equal and opposite concept, the shrunken area corresponds to the overlap area during the balls contact. CutShots instructs player to make a line from the contact point on the object ball to the cue ball so as to make the same amount of overlap area on the cue ball as on the object ball — an area opposite to and equal to the shrunken area on the object ball.
Straightline’s method is much easier to explain. It starts with two points: the object-ball contact point and the midpoint between the object and cue balls. The player connects those points. That is the aiming line.
Both methods then move the aiming line parallel toward the cue-ball center doing a Straightline “center point roll” to make the cue-stick aiming line.
Couple things about straightline's method. First, it's Wei table's revelation to me. Other posters used it sans chronology or credit so I'll call it the AZBE. E for epiphany. Previous to that I was the proud independent discoverer of reciprocal section overlap. Or overlaps as PJ calls 'em. Water...
The center point roll IIRC is some poster here I never refound his post or the thread(s) containing this mystical artifact. I find the, absence very odd - it's a fundamental set of truths. I'm not FBI eesnomyjob. So that.
Biggest effort required of CPR (lol) is finding the mid point. Went though various stages of standing off to the side and estimating with aerial hand spans until I could estimate accurately from the cue ball. Suddenly...
lol After many months of CPR it occurs to me that EAO gives you the midpoint; no guess work. I've come to consider
this crossing
wait for it...
THE MIGHTY X
taddahhh...
Take that Feijen.