AzBilliards.com Allowable Margin for Error -- Contact Point vs Fractional Aim Point
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 Allowable Margin for Error -- Contact Point vs Fractional Aim Point
 (#1) BC21 Poolology     Status: Offline Posts: 4,018 vCash: 500 iTrader: 2 / 100% Join Date: Feb 2017 Location: West Virginia Allowable Margin for Error -- Contact Point vs Fractional Aim Point - 03-03-2020, 02:13 PM I found this comparison interesting.... On a straight in shot the allowable margin for error when aiming at the exact ob contact point for a center pocket shot is relevant to the ob's margin of error going into the pocket. For example, an ob on the foot spot of a 7ft diamond barbox has a 4.5° window going cleanly into the pocket, a +/- 2.25° margin of error from center pocket. When measured across the surface of the ob (where the contact point is located) this 4.5° window provides a 2.2mm arc. If the cb strikes the ob anywhere within this arc the ob will go into the pocket. The same 2.2mm arc applies to cut shots also, but as the cut gets progressively thinner this 2.2mm becomes skewed. The change in perspective, as viewed from the cb, makes the 2.2mm arc look smaller. Straight in it looks like 2.2mm, but from a 1/2 ball hit perspective the 2.2mm looks like 1.9mm, and from a thinner 1/4 ball hit perspective it's only 1.5mm. Eventually, as the cut angle approaches 90°, the 2.2mm arc will not even be visible from the cb's perspective. So, when trying to reference the contact point, the margin for error shrinks as the cut angle increases. Compare this to fractional aiming, where the width of the ob (2.25") is used to partition the cb into quarter, eighth, or sixteenth aiming point references. This 2.25" never changes, regardless of cut angle/shot perspective. It's a constant. By ignoring the physical surface of the ball (sphere) you can simply focus on the diameter of the ball as a plain circle. Doing this doubles your margin of error when it comes to aiming references. Fractional aim points have 2 times the allowable margin for error when compared to contact points. A contact point arc of 2mm gives you room for error to be off by no more than 1mm left or right of perfect. The same shot using a fractional aim point allows for 4mm, meaning you can be off by as much 2mm left or right of the fractional aim point needed and still pocket the ball. Has anyone seen any information like this in any book or online resource? Just curious. Last edited by BC21; 03-03-2020 at 02:15 PM.

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03-03-2020, 06:45 PM

Quote:
 Originally Posted by BC21 I found this comparison interesting.... On a straight in shot the allowable margin for error when aiming at the exact ob contact point for a center pocket shot is relevant to the ob's margin of error going into the pocket. For example, an ob on the foot spot of a 7ft diamond barbox has a 4.5° window going cleanly into the pocket, a +/- 2.25° margin of error from center pocket. When measured across the surface of the ob (where the contact point is located) this 4.5° window provides a 2.2mm arc. If the cb strikes the ob anywhere within this arc the ob will go into the pocket. The same 2.2mm arc applies to cut shots also, but as the cut gets progressively thinner this 2.2mm becomes skewed. The change in perspective, as viewed from the cb, makes the 2.2mm arc look smaller. Straight in it looks like 2.2mm, but from a 1/2 ball hit perspective the 2.2mm looks like 1.9mm, and from a thinner 1/4 ball hit perspective it's only 1.5mm. Eventually, as the cut angle approaches 90°, the 2.2mm arc will not even be visible from the cb's perspective. So, when trying to reference the contact point, the margin for error shrinks as the cut angle increases. Compare this to fractional aiming, where the width of the ob (2.25") is used to partition the cb into quarter, eighth, or sixteenth aiming point references. This 2.25" never changes, regardless of cut angle/shot perspective. It's a constant. By ignoring the physical surface of the ball (sphere) you can simply focus on the diameter of the ball as a plain circle. Doing this doubles your margin of error when it comes to aiming references. Fractional aim points have 2 times the allowable margin for error when compared to contact points. A contact point arc of 2mm gives you room for error to be off by no more than 1mm left or right of perfect. The same shot using a fractional aim point allows for 4mm, meaning you can be off by as much 2mm left or right of the fractional aim point needed and still pocket the ball. Has anyone seen any information like this in any book or online resource? Just curious.
....................no

 (#3) CocoboloCowboy Cowboys are my heros.     Status: Offline Posts: 30,727 vCash: 1538 iTrader: 91 / 100% Join Date: Jul 2007 03-03-2020, 07:13 PM Aiming is like shooting a Rifle if the TARGETS "X" RING is 5 yards away hitting the "X" RING is easy. Move the Target out to 200 yards, you but not finish, more, or jerr the trigger. As if your Rifle move 1/4 of an inch at the point the bullet leave the barrel, by the time it travels 200 yards. If the entire Target is the size of a sheet of 8.5" X 11.00" letter head paper. Your bullet is not even on paper. If Pool was EASY every Nucklehead would play the game as good as Tiger Woods plays Golf. “Pool is geometry, in its most challenging form, the science of precise angles, and forces" - Quote from: A Game of Pool, The Twilight Zone 1961 Television Show.
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03-03-2020, 07:37 PM

Quote:
 Originally Posted by CocoboloCowboy Aiming is like shooting a Rifle if the TARGETS "X" RING is 5 yards away hitting the "X" RING is easy. Move the Target out to 200 yards, you but not finish, more, or jerr the trigger. As if your Rifle move 1/4 of an inch at the point the bullet leave the barrel, by the time it travels 200 yards. If the entire Target is the size of a sheet of 8.5" X 11.00" letter head paper. Your bullet is not even on paper. If Pool was EASY every Nucklehead would play the game as good as Tiger Woods plays Golf.
That sure is true. That's why a shorter bridge length can help reduce the bad effects of stroke errors for players with a faulty stroke, which helps them hit the cb more accurately. Distance makes everything harder and more sensitive to unwanted movements.

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03-03-2020, 07:40 PM

Quote:
 Originally Posted by BC21 Fractional aim points have 2 times the allowable margin for error when compared to contact points.
Lucy, you got some 'splaining to do.

pj
chgo

 (#6) BC21 Poolology     Status: Offline Posts: 4,018 vCash: 500 iTrader: 2 / 100% Join Date: Feb 2017 Location: West Virginia 03-03-2020, 07:50 PM Here is a diagram of what I'm talking about. Notice the contact point arc is 2mm. If the cb strikes the ob anywhere within this 2mm space the ob will go into the pocket. Carrying these trajectory lines back through the ob to where the center of the ghostball must be shows the limits of the ghostball location. If the ghostball is anywhere between the outer dots then the ob will hit the pocket. Using a halfball hit as a reference shows that there is twice as much room for aiming error when aiming at the edge of the ob, compared to the 2mm contact point margin on the curved surface of the ball.
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03-04-2020, 02:28 AM

Quote:
 Originally Posted by BC21 Using a halfball hit as a reference shows that there is twice as much room for aiming error when aiming at the edge of the ob, compared to the 2mm contact point margin on the curved surface of the ball.
Of course the actual physical margin of error is the same however you visualize it. Do you think there’s a practical difference?

pj
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BC21
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03-04-2020, 06:29 AM

Quote:
 Originally Posted by Patrick Johnson Of course the actual physical margin of error is the same however you visualize it. Do you think there’s a practical difference? pj chgo
Yes, I think there's a practical difference. Some people might find it easier to aim directly for a target area that is twice as wide as the contact point area, especially since the smaller contact point area isn't actually being aimed at directly. The player has to approximate the actual aim line based on his her experience or spatial skills/estimations.

Using the above halfball shot for an example, the player using contact points would need to keep the contact point in reference (within +/- 1mm of accuracy) and then estimate a parallel aim line or the opposite cb contact point in order to get the cue on the proper aim line. The ghostball user would need to estimate the exact ghostball location, which isn't visible, within an accuracy of slightly less than +/- 2mm (due to the angle of perspective). Using the fractional aim point, right edge of ob, (or for Duckie...the outermost surface on the right half of the ob) the player simply aligns the stroke/cue through ccb to this spot, give or take 2mm left or right of the spot.

The halfball aim is easy to be accurate with because there is a very defined visible reference -- the edge of the ob. If it were a 3/4 ball shot then the player would have to approximate a point halfway between ob edge and ob center. But there's wiggle room. With the above example as long as the player can estimate the 3/4 aimpoint within +/- 2mm the ball will go. Using the contact point requires a reference accuracy of +/- 1mm, then the player must also estimate the aim line based on the referenced contact point.

So yes, there is a very big practical difference between the two methods.

Many people that come here can already play pool, probably pretty well, and many more are just trying to learn. Reducing the amount of estimations, approximations, guesswork, trial and error, etc..., can really speed up the learning process. Experienced players are typically biased when it comes to teaching or helping new players learn the game. They teach what they do because that's how they learned. And they tell the newby, "you have to keep doing it, like this, like I do it, over and over... practice until you get good at it. That's the only way because there are no shortcuts."

I'm saying it's not the only way, and certainly not the most effective way. I'm saying there is a shortcut. Like most players, I can't show someone or explain to someone how I aim. I just do it, based on years of ghostball approximations I suppose. In the beginning the stroke is inconsistent, wonky, and so is the aiming approximation/estimation. It's hard to tell if a miss is due to a poor stroke mechanics or poor aiming experience. That's why it takes so much time -- there are two learning process developing at the same time.

I believe if a player can start off already knowing where to aim, using known aim points based on the width of the ob, they bypass the whole aiming approximation process, which can help build a consistent stroke in a much shorter amount of time. If you know exactly where to aim, no guesswork or experience needed, then missed shots can be attributed to flaws in stroke mechanics/cue delivery.

Last edited by BC21; 03-04-2020 at 06:34 AM.

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03-04-2020, 08:08 AM

Quote:
 Originally Posted by BC21 Using the fractional aim point, right edge of ob, the player simply aligns the stroke/cue through ccb to this spot, give or take 2mm left or right of the spot. Or what is even more visible would be the edge of the white CB to the center of the OB. It jumps out more clearly to the eyes and brain. The halfball aim is easy to be accurate with because there is a very defined visible reference -- the edge of the ob. Or the edge of the CB to COB. Or both for a double check. If it were a 3/4 ball shot then the player would have to approximate a point halfway between ob edge and ob center. But there's wiggle room. With the above example as long as the player can estimate the 3/4 aimpoint within +/- 2mm the ball will go. Using the contact point requires a reference accuracy of +/- 1mm, then the player must also estimate the aim line based on the referenced contact point. This is a little tougher using the fat center of the CB to a fat part of the OB. Or an equal and opposite fat part of both balls. There's considerable visual estimation and confusing visual static as you go up and down, back and forth between CB and OB to check, double check, and triple check to see if it's all aligned properly. Much easier using the edge of the CB to 1/4 or 3/4 of the OB. Jumps right out again to the eyes and brain. So yes, there is a very big practical difference between the two methods. I see where you're going with this and I tend to agree between contact points and fractions. Can you see the difference between using the crystal clear edge of the CB to areas on the OB being easier than both above? I can't show someone or explain to someone how I aim. I just do it, based on years of ghostball approximations. Why would it be that and NOT Poolology fractions if it's so mathematically correct? It just doesn't make sense and seems somewhat hypocritical.
My post is not to start or continue a war. Just as you're giving food for thought to PJ I'm doing likewise with you. Say STOP and I'll stop. Actually I will because I've said what I thought needed to be said.

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Last edited by SpiderWebComm; 03-04-2020 at 08:26 AM.

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03-04-2020, 08:43 AM

Quote:
 Originally Posted by SpiderWebComm My post is not to start or continue a war. Just as you're giving food for thought to PJ I'm doing likewise with you. Say STOP and I'll stop. Actually I will because I've said what I thought needed to be said.
You brought up some good points. The edge of cb referenced to the fractional divisions on the ob does pop out to the brain a little easier.

But the actual aim line is offset from this visual reference line. And honestly it's not difficult to visualize a line splitting the cb in half, right through the center. The ball is directly in front of you, a fixed left edge and a fixed right edge, and the middle is right there. Not much of a spatial skills challenge.

The same applies to the ob, which is always a circle (as captured by our eyes), and can always be divided into equal divisions based on its outermost left and right edges and the midway point (center) between those edges.

By treating the ob like a circle, not a sphere, there is no "fat" part of the ball. It's just a simple matter of aiming to a point somewhere along a horizontal straight line (the diameter of the circle). I don't think its very spatially challenging to look at a distance object and visualize splitting the width of that object into quarter increments, or smaller with just a little practice.

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03-04-2020, 09:03 AM

Quote:
 Originally Posted by BC21 You brought up some good points. The edge of cb referenced to the fractional divisions on the ob does pop out to the brain a little easier. But the actual aim line is offset from this visual reference line. And honestly it's not difficult to visualize a line splitting the cb in half, right through the center. The ball is directly in front of you, a fixed left edge and a fixed right edge, and the middle is right there. Not much of a spatial skills challenge. The same applies to the ob, which is always a circle (as captured by our eyes), and can always be divided into equal divisions based on its outermost left and right edges and the midway point (center) between those edges. I agree with the two paragraphs above. BUT, when you're doing your best to line up the dead center of the CB to multiple fractions between the center of the OB and edge of the OB spaced 2mm to 2 1/2 mm from one to the next all the way to the edge of the OB with eyes going back and forth...up and down...it gets confusing and second guessing steps in. By treating the ob like a circle, not a sphere, there is no "fat" part of the ball. It's just a simple matter of aiming to a point somewhere along a horizontal straight line (the diameter of the circle). I don't think its very spatially challenging to look at a distance object and visualize splitting the width of that object into quarter increments, or smaller with just a little practice.
Splitting it into quarters isn't that big of a deal visually. It's all of the in-betweens in millimeters.

But herein lies the biggie. With fractions and using the center of the CB, once you get beyond a half ball aim and hit there's nothing to aim at except for guesswork or possibly using the edge of the CB. You're aiming into dead space with CCB.

With contact points, you're still using an equal and opposite contact point all across the entire CB and OB to both edges.

In that respect I feel contact points are the winner.

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03-04-2020, 09:18 AM

Quote:
 Originally Posted by SpiderWebComm Why would it be that and NOT Poolology fractions if it's so mathematically correct? It just doesn't make sense and seems somewhat hypocritical.
Because how most of us learned to pocket balls involved a lot of subjective experience, using ghostball or contact points or traditional fractional guesswork or whatever. So to teach that to someone else would be like saying, "Here, do this for a few weeks or months or years, then you'll be good at it also."

Sure, that works. We've all been there. But it's time consuming. Poolology is intended to be used as a tool to bypass much of the subjective time-consuming process of learning to pocket balls. Like those little stickers that can be placed on the fretboard of a violin to help beginning violinists learn the exact location for playing a certain note. Sure, they can do it without that little sticker tool. They can spend hours upon hours playing slightly sharp or flat notes before finally getting a feel for playing each note accurately. Or they can use stickers to mark exactly where each note is and bypass those hours of hitting wrong notes.

If the violinist's brain can immediately begin the learning process with positive repetition, no trial and error or subjective learning time is needed, as far as learning where the fingers need to be in order to produce a desired note. The player still needs to develop finger strength, dexterity, and proper playing technique, just like a pool player still needs to develop all the fundamentals that allow for a good and consistent cue delivery.

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03-04-2020, 09:26 AM

Quote:
 Originally Posted by SpiderWebComm Splitting it into quarters isn't that big of a deal visually. It's all of the in-betweens in millimeters. But herein lies the biggie. With fractions and using the center of the CB, once you get beyond a half ball aim and hit there's nothing to aim at except for guesswork or possibly using the edge of the CB. You're aiming into dead space with CCB. With contact points, you're still using an equal and opposite contact point all across the entire CB and OB to both edges. In that respect I feel contact points are the winner.
If you look at a chain link fence in the distance, support poles every 6 to 8 feet, and then look right or left of where the fence ends, it's not difficult to visualize another 6 or 8 ft distance, or even 3 or 4 ft. Same thing with a pool ball. You can even use the edge of your shaft, or sight the edge of the cb to a place on the ob if it helps. I don't find it difficult to aim a quarter of a ball away from the ob edge, because I have the width of that ball to campare it to.

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03-04-2020, 09:33 AM

Quote:
 Originally Posted by BC21 Because how most of us learned to pocket balls involved a lot of subjective experience, using ghostball or contact points or traditional fractional guesswork or whatever. True, but are you saying old dogs can't learn new tricks if they are in fact better than what was learned initially? You're the one who came up with Poolology fractions and extol it's virtues for accuracy. You're probably also the most curious, verbally winded, and analytical regarding various aiming systems. How is it that for the life of you that it's impossible to dissect what your seeing and doing with your tried and true system to the point of being completely and totally dumfounded when it comes time to explaining it? If it's that GOOD, IT needs to be packaged and sold...not Poolology. So to teach that to someone else would be like saying, "Here, do this for a few weeks or months or years, then you'll be good at it also." Why not if it made sense and could be explained? You certainly SEE something when you're setting up. WHAT? Use your thought processes and verbal skills to describe it.
How to play the violin or playing the violin with all the words to put those paragraphs together could have been better spent on aiming pool balls the way you currently do it.

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03-04-2020, 09:40 AM

Quote:
 Originally Posted by BC21 I don't find it difficult to aim a quarter of a ball away from the ob edge, because I have the width of that ball to campare it to.
It isn't! Nor is a half ball or center to center ball. Which is why it is the absolute cornerstones of a certain way of aiming that creates so much furor. Makes no sense but we'll leave it at that.

Lets not go here at all because we know it's a hazard to one's health, physically and mentally.

Keep it to the ease and effectiveness of visually aligning balls by fractions or contact points.

My fault for even bringing it up but it is on subject.

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Last edited by SpiderWebComm; 03-04-2020 at 09:48 AM.

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