Double the Distance Aiming ???

bbb said:
there a re few steos you do that i dont under stand
first you say
start from the opposite (pocket) side of the contact point
is that on the part of the ball you cant see?
if you mean equal from centerline opposite from the side the contact point is on
dont then have to see the distance from vertical axis the contact point is first
and then use that distance to determine your second point ie the point opposite the contact point
then if i understand you you go from that point opposite the contact point to the contact poin and then to the aim point
correct please what i am misunderstanding please....
last your X's are on a diagonal
shouldnt they be horizontal on the equator?
Click to expand...
1. "is that on the part of the ball you cant see?"

Yes, the opposite side of the contact point relative to CB center, so imagine like where the actual contact point is relative to CB center, then mirror that to the other side, that's the point I start at.

2. "last your X's are on a diagonal, shouldnt they be horizontal on the equator?"

Basically I am visualizing the following (points in 3D space) in this order: Opposite of contact point, OB center, contact point, GB center. All of those 4 points fall along the same line, which is (from the POV of the shot line for a non-straight shot) diagonal and not horizontal on the equator because I am not flattening them out, but rather considering where they are in the 3D space.

1767642549281.png


Here is a top-down view:
1: Opposite of contact point
2: OB center
3: Contact point
4: GB center

The key idea is that no matter what perspective you are looking at, the distance between consequtive points is always equal, so diff between 1<->2 is same as 2<->3 and 3<->4. I visualize where point 1 is, then work backwards from there by jumping my gaze to 2, 3 and then finally 4. The reason I start at 1 instead of just 2 which is the more common approach, is that this one extra step gives me a better feel for the distance, which is helpful because as the distance stays the same between jumps, getting more repetitions of this jump makes it easier to judge the final jump from 3 to 4, which is the hardest to judge, compared to e.g. judging OB center or the contact point.

Once I have my gaze on point 4, I will align myself to shoot towards that point (doing necessary adjustments for side etc. if needed), then go down on the shot.

This method obviously requires good visualization of the contact points, and it is effectively just a longer method of arriving at ghost ball, which if you can visualize well, makes it easier to just skip all of these steps and go straight to aiming at the GB center. But if you don't visualize the GB well (which is the case for me), this method can be a good setup for finding GB center reliably. The whole thing typically takes like 3-4 seconds, and it gets faster the more you do it.

Another way of explaining why using point 1 at the start instead of just doing 2->3->4 helps is that you are doing two jumps, 1->2 and 2->3 before needing to jump to the GB location. Let's say it's a tough shot and you misjudge the jumps slightly, with jump 1->2 being slightly longer than 2->3. This signals you that you did something wrong, and then you can either re-attempt from the beginning or just take the average of those two jumps to minimize the error for the final jumps distance. This will produce better results than just starting from 2->3 and trusting that the distance was correct for 3->4.

Hope I explained it more clearly.
 
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Not Dead Ted said:
Even if the shot length shortens along the CB-GB line and there is no change in cut angle, the double the distance method has some pitfalls. See page 4-5 of
https://drdavepoolinfo.com/resource_files/Don_Smith_PIM.pdf.
Click to expand...
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.

Screenshot 2026-01-05 185953.png


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.


Screenshot 2026-01-05 173553.png


pj
chgo
 
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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...
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?
 
Oikawa said:
1. "is that on the part of the ball you cant see?"

Yes, the opposite side of the contact point relative to CB center, so imagine like where the actual contact point is relative to CB center, then mirror that to the other side, that's the point I start at.

2. "last your X's are on a diagonal, shouldnt they be horizontal on the equator?"

Basically I am visualizing the following (points in 3D space) in this order: Opposite of contact point, OB center, contact point, GB center. All of those 4 points fall along the same line, which is (from the POV of the shot line for a non-straight shot) diagonal and not horizontal on the equator because I am not flattening them out, but rather considering where they are in the 3D space.

View attachment 874372

Here is a top-down view:
1: Opposite of contact point
2: OB center
3: Contact point
4: GB center

The key idea is that no matter what perspective you are looking at, the distance between consequtive points is always equal, so diff between 1<->2 is same as 2<->3 and 3<->4. I visualize where point 1 is, then work backwards from there by jumping my gaze to 2, 3 and then finally 4. The reason I start at 1 instead of just 2 which is the more common approach, is that this one extra step gives me a better feel for the distance, which is helpful because as the distance stays the same between jumps, getting more repetitions of this jump makes it easier to judge the final jump from 3 to 4, which is the hardest to judge, compared to e.g. judging OB center or the contact point.

Once I have my gaze on point 4, I will align myself to shoot towards that point (doing necessary adjustments for side etc. if needed), then go down on the shot.

This method obviously requires good visualization of the contact points, and it is effectively just a longer method of arriving at ghost ball, which if you can visualize well, makes it easier to just skip all of these steps and go straight to aiming at the GB center. But if you don't visualize the GB well (which is the case for me), this method can be a good setup for finding GB center reliably. The whole thing typically takes like 3-4 seconds, and it gets faster the more you do it.

Another way of explaining why using point 1 at the start instead of just doing 2->3->4 helps is that you are doing two jumps, 1->2 and 2->3 before needing to jump to the GB location. Let's say it's a tough shot and you misjudge the jumps slightly, with jump 1->2 being slightly longer than 2->3. This signals you that you did something wrong, and then you can either re-attempt from the beginning or just take the average of those two jumps to minimize the error for the final jumps distance. This will produce better results than just starting from 2->3 and trusting that the distance was correct for 3->4.

Hope I explained it more clearly.
Click to expand...
double distance clear cue ball diagram.png

@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?
 
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.
 
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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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.
 
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I tried the DTD method. It seems to work at least most of the time. I missed a bunch of shots, though, before I started to get it right, especially as the cuts became more severe.

That said, since I have little trouble visualizing the ghost ball, I have a much better time (and shorter time!) simply aiming at the center of the imaginary ghost ball.

To those of you for whom this method works, good on you!
 
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Oikawa said:
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...
yes my diagram was more about the gist of things
i did not measure things out precisely
 
Patrick Johnson said:
If you want to double-the-distance you have to start with the estimated shot line.

pj
chgo
Click to expand...
?????
i may be having a definition problem
for me double the distance is looking center cue ball to center object ball
find the CONTACT POINT TO THE POCKET
on the object ball
double the distance from center object ball to contact point to find aim line
 
bbb said:
?????
i may be having a definition problem
for me double the distance is looking center cue ball to center object ball
find the CONTACT POINT TO THE POCKET
on the object ball
double the distance from center object ball to contact point to find aim line
Click to expand...
That works because the center-to-center and shot lines are usually close enough together that the small adjustment is made subconsciously. The difference only becomes noticeable as the balls get close together and the center-to-center and shot lines get far apart. This just means that double-the-distance, like all aiming systems, needs some user input.

pj
chgo
 
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