The contact patch is where any ball touches the table. With contact patch, you dont aim at the OB, you aim for a spot on the table that is 1/2 ball width from the OB.
Put a ball on the spot. Next freeze a ball to that ball such that it goes into one corner pocket. Place the CB some distance and angle from the spotted ball.
Remove the spotted ball. The spot now represents where the CB contact patch needs to roll over to make the ball go in the corner pocket.
With contact patch there is no need to look at the OB. If you look at the OB, you are not looking where the CB needs to be. By look at, I mean your central vision is on the OB.
Now go stand in a postion that is behind the OB and on a line to the center of the pocket. The spot is gonna be on that line also which is also the same line the OB contact point is on.
Now place the cues tip on the center on the spot and rotate till the center line of the cue is over the top of the cue ball.
Now you are on the shot line.
This is nothing new. What I have done is just added more detail to Babe Cranfields spot on the table he taught. His training aid the arrow points to the to where the CB contact patch needs to be.
And there you have it……..and no 13 chapters needed to explain it.