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DeadCrab
05-31-2007, 03:03 PM
If you like to set up your shots by positioning your cue along the aiming line, here is a good way to get an estimate of the cut angle (between aiming and impact lines). I use this a lot for angles of 5-20 degrees, especially for long shots.

The perpendicular distance, x, between the aim and impact lines follows the relationship x = h *sin (cutangle)

For a 58 inch cue on the aim line, x = 59sin(cutangle)

This has the very convenient relationship that it simplifies to (approximately): x (in inches)= cutangle(degrees).

So, if you are lining up a long shot, and set the cue down on the aim line with tip near the OB, and the butt end of the cue is 8.5 inches from the impact line, then the cut angle is 8.5 degrees.

For shorter shots, the cue joint can be used as the point to measure from, and:

(2 * z) = cutangle, where z is the distance in inches from the joint to the impact line.

Example: Joint is 9" from impact line --> cut angle=18 deg

In anticipation of the question, "why is that easier than guessing the angle?", it is because a) linear distance in inches is easier for most of us to gague, and b) the hand is a great measuring device. My max handspan is 9", 3.25" across the fingers at the first joint. Hold the cue with one hand, use the known dimensions of your other hand to approximate the distance.

How I translate the cut angle to an aimpoint on the OB is another post.

cushioncrawler
05-31-2007, 06:32 PM
DeadCrab -- I karnt see much worth in getting a better view or idea of any fullish sorts of cuts. But, i allways have a special look at very thin cuts. I lean out over the OB and look straight down on it (if i can) -- i hold my cue along (over) the qball'to'OB line, and i imagine a 90dg cut angle for the OB, and imagine where that 90dg line cuts the cushion (near the pocket). Sometimes the 90dg line shows me that the cut is impossible. For makeable cuts, the 90dg line givz me a good idea of how much angle i have up my sleeve, ie inside 90dg. Otherwize, it is difficult to judge thin cuts from "behind" the qball or when u are "down on the shot", unless u praktis fine cuts all the time. madMac.

Jal
05-31-2007, 11:07 PM
<blockquote><font class="small">Quote DeadCrab:</font><hr>
If you like to set up your shots by positioning your cue along the aiming line, here is a good way to get an estimate of the cut angle (between aiming and impact lines). I use this a lot for angles of 5-20 degrees, especially for long shots.

The perpendicular distance, x, between the aim and impact lines follows the relationship x = h *sin (cutangle)

For a 58 inch cue on the aim line, x = 59sin(cutangle)

This has the very convenient relationship that it simplifies to (approximately): x (in inches)= cutangle(degrees).

So, if you are lining up a long shot, and set the cue down on the aim line with tip near the OB, and the butt end of the cue is 8.5 inches from the impact line, then the cut angle is 8.5 degrees.

For shorter shots, the cue joint can be used as the point to measure from, and:

(2 * z) = cutangle, where z is the distance in inches from the joint to the impact line.

Example: Joint is 9" from impact line --&gt; cut angle=18 deg

In anticipation of the question, "why is that easier than guessing the angle?", it is because a) linear distance in inches is easier for most of us to gague, and b) the hand is a great measuring device. My max handspan is 9", 3.25" across the fingers at the first joint. Hold the cue with one hand, use the known dimensions of your other hand to approximate the distance.

How I translate the cut angle to an aimpoint on the OB is another post. <hr /></blockquote>It's a very interesting way of determining the cut angle, which few have probably discovered. It never occurred to me that you could just sort of "read it off the cloth". And to the extent that you can measure or judge the distance x reasonably well, it's pretty accurate for angles up to and a little beyond 30 degrees.

There is a bit of begging the question though. You don't know the aim line unless you already know the aim line, in which case the procedure seems a little redundant. But I still think it's a nice insight if you want to put a number on the cut angle.

I also agree with Mac's criticism. Anyone who has played for a while should be able to just see the aim line (which your method assumes anyway) I would think as accurately as what you get by doing the geometry, which involves errors at each step of the way.

Jim

DeadCrab
06-01-2007, 06:57 AM
I should have made it clear that I was calling the line between cueball and object ball centers the "aim" line, even though it is not. I didn't know what else to call it, perhaps CB-OB line would have been better.

I determine my aim line based on an estimate of the angle, which I then relate to a specific target on the OB. As a beginner, I like an exact target to shoot at, as this allows me to focus on delivery (stroke), and cueball control. When I miss, the issue is not really one of shot setup, but either a failure to hit it, or lack of compensation for throw and spin.

Jal
06-01-2007, 08:04 AM
<blockquote><font class="small">Quote DeadCrab:</font><hr>
I should have made it clear that I was calling the line between cueball and object ball centers the "aim" line, even though it is not. I didn't know what else to call it, perhaps CB-OB line would have been better.<hr /></blockquote>CB-OB line sounds good. Thanks for the clarification.

<blockquote><font class="small">Quote DeadCrab:</font><hr>I determine my aim line based on an estimate of the angle, which I then relate to a specific target on the OB....<hr /></blockquote>So then how do you go about finding the aim line and target?

Jim

DeadCrab
06-01-2007, 09:07 AM
When looking straight down the CB-OB line, the target point for a cut angle of x degrees, is approximately x mm from the center of the OB. A 13.5 degree cut has aim point 13.5mm off the center (not surface) of the OB.

Because the OB is spherical, localizing this as a fixed point on the equator is difficult. I look at the bottom of the ball, and view it as 2-dimensionally as I can. Because the ball sinks into the cloth a bit, there is no space visible between the ball and cloth for the first few mm off center. For my table, 5mm off center (5 degree cut) is just where the ball can be seen separating from the cloth.

I took a full scale pool ball diagram (available at the sfbilliards site), and measured off 5, 10, 15, 20, and 25mm on the horizontal axis. I then measured up from the x axis to find how high the edge of the ball would be off the table, and found:

5mm off center --&gt; 1mm up from table surface
10mm --&gt; 2mm
15mm --&gt; 4mm
20mm --&gt; 8mm
25mm --&gt;18mm

Say I have a 20 degree cut. I look for the point on the cloth 20mm off the cue center, and confirm that the ball edge is about 8mm off the table surface. This double check has helped my localization a lot. A triple check can also be done for some cuts; for example, the correct aim point for a 15 degree cut is 30 degrees off vertical (5 o'clock and 7 o'clock), and a 20 degree cut about 45 degrees off vertical.

To sharpen my eye, I took one of the paper ball templates, and marked the aim points for several angles, and taped it to my computer at work where I can give it a look during dead time. I have deep cloth, and have to reduce my vertical coordinate a mm or so to compensate, but for fast cloth I doubt much adjustment would be needed.

dr_dave
06-01-2007, 09:36 AM
<blockquote><font class="small">Quote Jal:</font><hr>It's a very interesting way of determining the cut angle, which few have probably discovered. It never occurred to me that you could just sort of "read it off the cloth". And to the extent that you can measure or judge the distance x reasonably well, it's pretty accurate for angles up to and a little beyond 30 degrees.

There is a bit of begging the question though. You don't know the aim line unless you already know the aim line, in which case the procedure seems a little redundant. But I still think it's a nice insight if you want to put a number on the cut angle.

I also agree with Mac's criticism. Anyone who has played for a while should be able to just see the aim line (which your method assumes anyway) I would think as accurately as what you get by doing the geometry, which involves errors at each step of the way.<hr /></blockquote>Jim,

Good points! For people who have trouble visualizing the aiming line, impact line, and cut angle, NV 3.1 (http://www.engr.colostate.edu/~dga/pool/normal_videos/NV3-1.htm) and NV 3.2 (http://www.engr.colostate.edu/~dga/pool/normal_videos/NV3-2.htm) might be of interest. If learning to put a number on the cut angle is important, my cut angle template (http://www.engr.colostate.edu/~dga/pool/resources/cut_angle_template.pdf) might also be of interest.

Regards,
Dave

DeadCrab
06-01-2007, 11:46 AM
*********
Good points! For people who have trouble visualizing the aiming line, impact line, and cut angle, NV 3.1 and NV 3.2 might be of interest. If learning to put a number on the cut angle is important, my cut angle template might also be of interest.
*************************

Your template shows the angles through the imaginary ghost ball. The method I have described is for those who prefer to target a real physical point, rather than one imagined.

As an engineer, I would think you would appreciate the potential benefits of tangible vs. intangible, but apparently not.

dr_dave
06-01-2007, 12:13 PM
<blockquote><font class="small">Quote DeadCrab:</font><hr>
*********
Good points! For people who have trouble visualizing the aiming line, impact line, and cut angle, NV 3.1 and NV 3.2 might be of interest. If learning to put a number on the cut angle is important, my cut angle template might also be of interest.
*************************

Your template shows the angles through the imaginary ghost ball. The method I have described is for those who prefer to target a real physical point, rather than one imagined.

As an engineer, I would think you would appreciate the potential benefits of tangible vs. intangible, but apparently not. <hr /></blockquote>I meant no offense. I'm sorry if you took offense at what I wrote.

I love tangibles, but aiming is tough to quantify for most people. You can talk about and illustrate "tangibles" like impact line, cut angle, CB-OB contact point, ball-hit fraction, and the ghost-ball center; but when many people aim and get down on a shot, they just "see the angle" and visualize the required aiming line (and maybe consciously or subconsciously make fine adjustments for squirt, swerve, and throw), without quantifying anything. The techniques in NV 2.1 and NV 2.2 (http://www.engr.colostate.edu/~dga/pool/normal_videos/index.html) just help beginners practice their visualization. FYI, lots of more info and discussion on aiming systems can be found under "aiming" here (http://www.engr.colostate.edu/~dga/pool/threads.html).

Regards,
Dave

DeadCrab
06-01-2007, 01:37 PM
***
I love tangibles, but aiming is tough to quantify for most people.
*******

When there is important aiming to be done, like firing artillery shells or putting a satellite in orbit, it isn't done by "feel". You do the calculations and hammer it home.

There are a lot of people who can't see the parallel lines, impact points, or ghost ball, who still know which wrench to pick up by eyeballing a bolt eight feet away.

Amongst the many wonderful technical proofs on your site, there is not one for aiming. That, is apparently left to the
humanities types. Judging from the frequency at which this subject comes up on this forum and others, I'd say it isn't working for a lot of people.

Anyway, that's how I aim, and with that issue resolved I can concentrate on finding a stroke.

dr_dave
06-01-2007, 03:12 PM
<blockquote><font class="small">Quote DeadCrab:</font><hr>Amongst the many wonderful technical proofs on your site, there is not one for aiming. That, is apparently left to the
humanities types. Judging from the frequency at which this subject comes up on this forum and others, I'd say it isn't working for a lot of people.<hr /></blockquote>Actually, I have quite a lot of stuff on my site dealing with aiming (and even more dealing with stroke, which probably causes more problems than aiming for most people). For example, see: <ul type="square"> video demonstrations under Chapters 2 and 3 related to aiming (http://www.engr.colostate.edu/~dga/pool/normal_videos/index.html) (especially NV 3.1 and 3.2). TP A.11, A.12, A.14, A.15, and other technical analyses related to aim (http://www.engr.colostate.edu/~dga/pool/technical_proofs/index.html). many of my throw and other articles (http://www.engr.colostate.edu/~dga/pool/bd_articles/index.html) dealing with the need to adjust one's aim. many of my templates, drills, and summaries (http://www.engr.colostate.edu/~dga/pool/resources/index.html) for helping people practice their aim. numerous useful summaries and resources concerning aiming under "aiming" here (http://www.engr.colostate.edu/~dga/pool/threads.html).[/list]
Aiming is just tough for people because it requires good spatial visualization skills, good vision, good depth perception, good intuition on how to adjust for different effects (e.g., squirt, throw, and swerve), and lots of practice. I can't think of any technical analyses that would likely lead to any new insights. I'd rather put my efforts elsewhere, where I think I can make a difference. It isn't my intent to discourage you or others to pursue this ... I just don't feel it is worthwhile for me to pursue it further.

Regards,
Dave

cushioncrawler
06-01-2007, 04:37 PM
I still say that praktis is the key. The way i praktis is that i try to learn the halfball angles firstly -- i set up the qball and OB in all sorts of (what i think are) halfball pozzyz and i hit the OB halfball and see what happens -- then i moov one or other untill it is exactly halfball -- then i play that shot over and over -- then i play the "same shot" but with the qball closer or furtherer. Etc etc. One problem, halfball cuts to the left will look different to halfball cuts to the right -- its the eyes, and/or the lights. When u have come to grips with every pozzy on the table (after say 1 year), then u can try 3/4ball shots. The next year, 1/4ball shots. Just joking. madMac.

Jal
06-01-2007, 05:30 PM
<blockquote><font class="small">Quote DeadCrab:</font><hr>
When looking straight down the CB-OB line, the target point for a cut angle of x degrees, is approximately x mm from the center of the OB. A 13.5 degree cut has aim point 13.5mm off the center (not surface) of the OB.<hr /></blockquote>That's another interesting point which few are likely to be aware of (I wasn't).

<blockquote><font class="small">Quote DeadCrab:</font><hr>Because the OB is spherical, localizing this as a fixed point on the equator is difficult. I look at the bottom of the ball, and view it as 2-dimensionally as I can. Because the ball sinks into the cloth a bit, there is no space visible between the ball and cloth for the first few mm off center. For my table, 5mm off center (5 degree cut) is just where the ball can be seen separating from the cloth.

I took a full scale pool ball diagram (available at the sfbilliards site), and measured off 5, 10, 15, 20, and 25mm on the horizontal axis. I then measured up from the x axis to find how high the edge of the ball would be off the table, and found:

5mm off center --&gt; 1mm up from table surface
10mm --&gt; 2mm
15mm --&gt; 4mm
20mm --&gt; 8mm
25mm --&gt;18mm

Say I have a 20 degree cut. I look for the point on the cloth 20mm off the cue center, and confirm that the ball edge is about 8mm off the table surface. This double check has helped my localization a lot. A triple check can also be done for some cuts; for example, the correct aim point for a 15 degree cut is 30 degrees off vertical (5 o'clock and 7 o'clock), and a 20 degree cut about 45 degrees off vertical.

To sharpen my eye, I took one of the paper ball templates, and marked the aim points for several angles, and taped it to my computer at work where I can give it a look during dead time. I have deep cloth, and have to reduce my vertical coordinate a mm or so to compensate, but for fast cloth I doubt much adjustment would be needed. <hr /></blockquote>Given the longish history of pool, and all of the technical types that have looked at it, you're aiming method has probably been discovered prior to you, but it certainly must be rare if not unique to you.

I probably don't have to mention that you can make an adjustment to your measured angle (refering to your first post), by adding the approach or ghost ball angle ("beta" in the first diagram of Dr. Dave's TP A_29), which yields the true cut angle "phi" in his diagram. Beta is usually very small, but technically "cut angle" means the angle between the cueball's direction and the impact line, which is in fact how you're using it compute the offset of your target. Estimating beta as a first approximation should be good enough, if you bother to do it at all.

Thanks for the interesting and novel observations(s). I do believe that eventually you will rely on intuition, mainly if not exclusively, but who knows?

Jim

Fran Crimi
06-02-2007, 07:22 AM
<blockquote><font class="small">Quote DeadCrab:</font><hr>
I should have made it clear that I was calling the line between cueball and object ball centers the "aim" line, even though it is not. I didn't know what else to call it, perhaps CB-OB line would have been better.

I determine my aim line based on an estimate of the angle, which I then relate to a specific target on the OB. As a beginner, I like an exact target to shoot at, as this allows me to focus on delivery (stroke), and cueball control. When I miss, the issue is not really one of shot setup, but either a failure to hit it, or lack of compensation for throw and spin. <hr /></blockquote>

I like your aiming system. I guess I'm one of the guilty ones who claims to aim by 'feel' but I recognize that there are players who prefer a more exact target.

One thing I've learned from teaching pool is that it's not so much whether you're a beginner or not, but rather how you take in information. I've taught beginners who need more exactness and beginners who play more by 'instinct,' for lack of a better word. Those instinctive-type players are a challenge to teach because I have to appeal to them on another level, but nonetheless, there is order to their chaos, and being one myself, I can relate.


Nice job.

Fran

dr_dave
06-02-2007, 07:32 AM
<blockquote><font class="small">Quote Fran Crimi:</font><hr> <blockquote><font class="small">Quote DeadCrab:</font><hr>
I should have made it clear that I was calling the line between cueball and object ball centers the "aim" line, even though it is not. I didn't know what else to call it, perhaps CB-OB line would have been better.

I determine my aim line based on an estimate of the angle, which I then relate to a specific target on the OB. As a beginner, I like an exact target to shoot at, as this allows me to focus on delivery (stroke), and cueball control. When I miss, the issue is not really one of shot setup, but either a failure to hit it, or lack of compensation for throw and spin. <hr /></blockquote>

I like your aiming system. I guess I'm one of the guilty ones who claims to aim by 'feel' but I recognize that there are players who prefer a more exact target.

One thing I've learned from teaching pool is that it's not so much whether you're a beginner or not, but rather how you take in information. I've taught beginners who need more exactness, and beginners who play more by 'instinct,' for lack of a better word. Those instinctive-type players are a challenge to teach, because I have to appeal to them on another level, but nonetheless, there is order to their chaos, and being one myself, I can relate.


Nice job.

Fran<hr /></blockquote>Fran,

Welcome back!!! You've been gone for a while. I look forward to the opportunity to "start off on a new foot with you." I hope you are back to stay. The CCB is a much better forum with your participation.

Regards,
Dave

Duckie
06-02-2007, 04:03 PM
Get "The Straight Pool Bible" by Babe Cranfield and use his arrow template. That will help with where to aim.

Basiclly, extended the object ball line of travel from the pocket through the object ball by half a ball. Thats where the cue ball needs to be put. Then adjust for spin as needed.

cushioncrawler
06-02-2007, 06:37 PM
<blockquote><font class="small">Quote Duckie:</font><hr> ...Basiclly, extended the object ball line of travel from the pocket through the object ball by half a ball. Thats where the cue ball needs to be put. Then adjust for spin as needed.<hr /></blockquote>Duckie -- I have to admit that i could never come to grips with all of the aiming systems out there, like extending a line from the pocket a half ball, or imagining the needed ball'to'ball contact point etc. I simply imagine a flat 2-dimensional circle (qball) overlapping a flat 2-dimensional cicle (OB), the amount of overlap giving the needed OB angle. Even then, i simplyfy this even further, koz i find that i rarely ever need to aim other than 1/4ball or 1/2ball or 3/4ball or 4/4ball, and use a bit of pivot (if needed) to add or subtract a few degrees of angle. Not meaning to start a counter-thread here, but perhaps someone allready dizzy from imagining lines and half-radius points etc, mightnt fall over if going further and imagining handspans etc. madMac.
madMac.

Duckie
06-04-2007, 12:05 AM
What the arrow really is a aiming device that can be made based on the size of the balls used. Bob Jewett did a aiming article that showed the arrow. Once made, it is placed under the object ball with a point that is 1/2 ball in front of the object ball. Put the cue ball on the point, the object ball goes in the pocket as long as the point is placed in line with the path needed for the object ball to go in the pocket. Of course the point is just a extention of the contact point on the object ball that will put the object ball in the pocket.

DeadCrab
06-04-2007, 06:41 AM
When it comes to aiming, it is a very individual choice. With time, any method will likely give way to intuition with time and experience. All aiming systems (that work) put the cue ball in the same place. The only difference is in how that point is localized.

I'm a concrete person, who prefers a specific on-ball point to shoot at. I couldn't find any aiming systems out there that addressed this. I was really motivated to find something that worked for me when I built my home table with 4.25" pockets. The aim has to be pretty good.

I'm still a beginner hack, but changing to this approach has moved me from a straight pool 3-4 ball run hacker to a 7-8 ball runner, a level where I think I can start focusing on aspects of the game beyond aiming.

It isn't for everybody. But if angle and distance estimation and "real" targets are your thing, it might help your game.

Duckie
06-04-2007, 10:10 AM
Yep its nice that there are so many aiming systems cause there is bound to be one that will work for a person.

I could never get the 1/4, 1/2 ball one or think of degrees of angle and so on. One day I drew two circles touching each other. One was the object ball, the other the cue ball.

I drew a line from where they touched, cutting the object ball circle in half going, toward a pocket. Then I drew a line from the center of the cue ball circle over the object ball line going in the same direction.

Then, at the center of the cue ball circle, I drew a line 45 degrees to the orginal cue ball line. Then more lines at various angles. What I noticed was that no matter the angle, the cue ball center was always 1/2 the cue ball circle diameter from the object ball circle. This little exercise really helped me.

I thought I had a "new' aiming system until I read the Straight Pool Bible and saw the arrow device Cranfield devolped.

jondrums
11-13-2007, 04:26 PM
Hey guys, I was refered to this post because of a system I just put up (which is very similar) to the one in this post. But discussion turned to aiming templates, and I figured I should post the one I made for anyone to use. Just print it out, cut it out, and use it. I hope it helps someone out there sometime. I never posted it here, because attachments are not allowed. link to azbilliards post with the .pdf template (http://forums.azbilliards.com/showthread.php?t=44853&amp;highlight=aiming+template)

Jon

jondrums
11-13-2007, 04:43 PM
DeadCrab-
I might respectfully mention that your system could be improved pretty easily to be more accurate - especially for larger angles. Using a right angle is a passable method for small angles, but if you use the unique end of an isosceles triangle as your distance measure, you'll improve the system's accuracy. see images below:
http://i237.photobucket.com/albums/ff105/jondrums/right_angle_system.jpg http://i237.photobucket.com/albums/ff105/jondrums/issocolese_system.jpg

Also take a look at a system I independently worked out. It is very similar, but for me is much easier to quickly find exactly a 1/4 or 1/2 or 3/4 ball hit because it is "precalibrated" to the length of your handspan.

look here (http://www.billiardsdigest.com/ccboard/showflat.php?Cat=&amp;Board=ccb&amp;Number=264378&amp;page=0&amp;v iew=collapsed&amp;sb=5&amp;o=&amp;fpart=1&amp;vc=1)

Jon

dr_dave
11-13-2007, 05:51 PM
FYI, I also have printable cut-angle and other templates available here (http://billiards.colostate.edu/resources/index.html). Thank you for posting yours.

Regards,
Dave
<blockquote><font class="small">Quote jondrums:</font><hr> Hey guys, I was refered to this post because of a system I just put up (which is very similar) to the one in this post. But discussion turned to aiming templates, and I figured I should post the one I made for anyone to use. Just print it out, cut it out, and use it. I hope it helps someone out there sometime. I never posted it here, because attachments are not allowed. link to azbilliards post with the .pdf template (http://forums.azbilliards.com/showthread.php?t=44853&amp;highlight=aiming+template)

Jon <hr /></blockquote>