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Double the Distance Aiming ???

Oikawa
bbb said:
View attachment 874724
@Oikawa
i hope you can follow me with this diagram
forget about the cue ball and 7 ball in the back ground
pretend there is a cue ball in line with this clear we will call the object ball so the both balls are parrallel with the short rail
in other words you are standing behind the cue ball going to pocket this ball in the side pocket
yellow line is the shot line
#1 is where the shot line contacts the rounded part of the object ball
you then "see " the distance of the yellow line from there to the red dot thats #2
i see things flat so thats the green line above
point #3 is the same distance from #1 to the red dot which you see along the yellow line
then your aim line #4 is that same distance from #3 along the yellow line( i did not put an arrow there and it took to long for me to go back and recreate this diagram!!!!!)
do i have that correct?
Click to expand...
Yes, this is correct. And yes, I use the 3D points because thats where the contact/opposite contact points are in reality, so for me it's easier to just use their real positions and not flatten it out. But in theory it's the same whether you flatten the y-axis out or not, the x-axis position of the GB center is what matters at the end, no matter how you get there.

The only caviat with that image is that the real contact point position would be different for that cut shot, but it's besides the point. The method is what you asked about, and the description was correct, even if the image has an incorrect judgement of the contact point.
Click to expand...

Double the Distance Aiming ???

H
bbb said:
the line of sight for the measurement is the shot line, parallel with the cue.
i am confused
if you are visualizing the center of the cue ball with the center of the shot line you have a straight in shot
in your other pic below i dont understand how the red lines give you the aim lines
sorry for being so dumb....what am i missing?
Click to expand...
The "line of sight" is parallel to the cue/stroke line, but for the DTD sighting, that line is offset from a parallel line that runs through the object ball. Considering the graphic, the original, black lines have both balls on the same line--running North-South, so to speak. If you were to turn the diagram clockwise, so that the red lines were then running N-S, then you can see the offset, and it shows the correct way to determine the DTD aiming.
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Double the Distance Aiming ???

N
Patrick Johnson said:
That diagram illustrates the same visualization error - the center of the OB is viewed along the center-to-center line instead of along the shot line as needed. The red lines below show how it should be viewed/measured.

View attachment 874461

Double-the-distance aiming works the same even when the CB/OB are touching. The black lines below go through the center of the CB, the edge of the CB and midway between (which, as we know, is where the contact point always is). As you can see, the line of sight for the measurement is the shot line, parallel with the cue.


View attachment 874431

pj
chgo
Click to expand...
Yeah, if you know the red line orientation, you don't have to double anything, because the problem has already been solved. Unfortunately, the player does not know the orientation. To find it, the author is advocating doubling of the radius along the OB-pocket line, which is just another way to visualize the ghost ball center. For those who can do this for CB-OB distances of 8 cm to 8 ft, the aiming problem is solved and they can move on to other things.
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