lol I think I've already overcomplicated it.
Who said anything about useful?
pj
chgo
A Little Help With Math Please
- Thread starter Johnnyt
- Start date
pj
chgo
Well that's ironic. You're trying to measure margin of error by only looking at the angles that have the least error.
I'm giving examples. If you think an overall margin of error can be calculated, you're free to try that.
pj
chgo
I swear this should be nominated for post of the year.
It's what most of us should be doing anyway!
Quote:
Originally Posted by ElCorazonFrio View Post
This attachment is horribly incomplete. This only works for approaching the pocket in the limited angle where the entire mouth of the pocket is visible.
------------------------------------------------------------------------------------------------------------
Yes indeed - shame on you for posting a chart so horrible...
My self, I was only horrified by the thought of the amount of time it must have taken
to calculate the data you did provide.
IMHO - one could generate some kind of all inclusive angle/distance/effective pocket size presentation.
But it would require formulae with trig functions... you know sines and cosines and arctans, and stuff.
Perhaps frito would like to make us one.
Dale(formulator at large)
So I did a very rude draw up in Visio to see how much contact point you have and how missing that by only 1 degree would affect a shot.
I made 2 cue balls and inserted a cut angle line at every degree 0-90. I then lined them up on a 45 degree line for a straight shot and put them as close as I could with no overlap. The difference between each degree is about .019 inches (just over 1/64"). Not accounting for elasticity of balls, the contact point appears to be just over 1/32nd of an inch at about .04". However this appears to contain 2 degrees and then a tad.
I then extended the straight shot line (0 degrees) out 4ft and then the 1 degree line out 4ft. At that point the shot was off 13/16th of an inch.
Clearly cut shots have CIT, but I ignored that for this purpose as you should be adjusting for that anyway plus I used a straight on shot to further ignore it.
Intentional or even accidental spin on the cue ball will also affect this as you could use SIT, but again I ignore that as I was going for pure angles and the affect they have on accuracy.
So with the above you can loosely conclude that a shot that gives a margin of error of 3" from 4ft away can be missed by about 1.7836 degrees on either side of center contact point and still be made. So in essence you have about a 1/8th inch contact point to hit on that shot.
As I said I used Visio and not some high accuracy CAD program, so be nice.
I made 2 cue balls and inserted a cut angle line at every degree 0-90. I then lined them up on a 45 degree line for a straight shot and put them as close as I could with no overlap. The difference between each degree is about .019 inches (just over 1/64"). Not accounting for elasticity of balls, the contact point appears to be just over 1/32nd of an inch at about .04". However this appears to contain 2 degrees and then a tad.
I then extended the straight shot line (0 degrees) out 4ft and then the 1 degree line out 4ft. At that point the shot was off 13/16th of an inch.
Clearly cut shots have CIT, but I ignored that for this purpose as you should be adjusting for that anyway plus I used a straight on shot to further ignore it.
Intentional or even accidental spin on the cue ball will also affect this as you could use SIT, but again I ignore that as I was going for pure angles and the affect they have on accuracy.
So with the above you can loosely conclude that a shot that gives a margin of error of 3" from 4ft away can be missed by about 1.7836 degrees on either side of center contact point and still be made. So in essence you have about a 1/8th inch contact point to hit on that shot.
As I said I used Visio and not some high accuracy CAD program, so be nice.
Last edited:
Checking with calculus, it looks like your results are pretty accurate.So I did a very rude draw up in Visio to see how much contact point you have and how missing that by only 1 degree would affect a shot.
I made 2 cue balls and inserted a cut angle line at every degree 0-90. I then lined them up on a 45 degree line for a straight shot and put them as close as I could with no overlap. The difference between each degree is about .019 inches (just over 1/64"). Not accounting for elasticity of balls, the contact point appears to be just over 1/32nd of an inch at about .04". However this appears to contain 2 degrees and then a tad.
I then extended the straight shot line (0 degrees) out 4ft and then the 1 degree line out 4ft. At that point the shot was off 13/16th of an inch.
Clearly cut shots have CIT, but I ignored that for this purpose as you should be adjusting for that anyway plus I used a straight on shot to further ignore it.
Intentional or even accidental spin on the cue ball will also affect this as you could use SIT, but again I ignore that as I was going for pure angles and the affect they have on accuracy.
So with the above you can loosely conclude that a shot that gives a margin of error of 3" from 4ft away can be missed by about 1.7836 degrees on either side of center contact point and still be made. So in essence you have about a 1/8th inch contact point to hit on that shot.
As I said I used Visio and not some high accuracy CAD program, so be nice.
pj
chgo
ElCorazonFrio
Banned
Quote:
Originally Posted by ElCorazonFrio View Post
This attachment is horribly incomplete. This only works for approaching the pocket in the limited angle where the entire mouth of the pocket is visible.
------------------------------------------------------------------------------------------------------------
Yes indeed - shame on you for posting a chart so horrible...
My self, I was only horrified by the thought of the amount of time it must have taken
to calculate the data you did provide.
IMHO - one could generate some kind of all inclusive angle/distance/effective pocket size presentation.
But it would require formulae with trig functions... you know sines and cosines and arctans, and stuff.
Perhaps frito would like to make us one.
Dale(formulator at large)
Hey, Dull,
Pj's chart took one easy equation and plugging in a few numbers. It wouldn't be hard to calculate the same numbers for all effective pocket widths and GRAPH it...pretty easy, really.
Dang, it'd be horrible if it used trigonometry...something most have a grasp on by the time they are 17.
I have no interest in doing this because it is useless. For a moment I thought it might be interesting, but then I remembered that it is simply the application of similar triangles (ooo...geometry...no trig even required...now any highschool freshman can do it).
I wasn't insulting anyone, Dull. I was pointing out something that I never saw covered in PJ's explanation...you know, in case people thought it was comprehensive.
Take care, Dull. Keep licking PJ's boots...I think you missed a spot.
Yup.
Yup. Feel free.
You mean this didn't cover it? "NOTE: These results are all for optimal approach angles"
pj
chgo
Be lazy like me and just shell out the cash :
http://www.muellers.com/Koehlers-The-Science-of-Pocket-Billiards-,2227.html
Dave <-- has programmed Ti58s to pass engineering exams but still just bought the book :thumbup:
PS Merry Christmas Dale :smile:
PPS Johnny, that not thinking thing seems to work for you, stick with it !
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I don't understand why you are all wasting so much time calculating results that are pretty much meaningless. The results would only be significant if it actually showed the difference between making a ball and missing a ball.
You can't possibly do that, because you are leaving out all of the angles in which a ball is pocketed but hits a part of the rail before going in the pocket. Once you include those angles, which is necessary to provide meaningful results, you introduce several table-specific variables that you can't account for. These include the speed of the shot, the type and wear of the felt, the rails, etc.
You can't possibly do that, because you are leaving out all of the angles in which a ball is pocketed but hits a part of the rail before going in the pocket. Once you include those angles, which is necessary to provide meaningful results, you introduce several table-specific variables that you can't account for. These include the speed of the shot, the type and wear of the felt, the rails, etc.
I doubt that I "wasted" as much time cutting and pasting that old chart as you did questioning the usefulness of it.
This kind of info is pretty much useless for practical purposes no matter how much detail is included.
pj
chgo
That's debatable, since I only took a minute or two. Why an old chart exists in the first place is beyond me. Then there are the other posts in this thread with detailed math that obviously took more effort than it was worth.
Exactly my point.
Exactly what is your point? That we shouldn't talk about things you don't find useful? Sorry, I didn't get the list.
pj
chgo
It actually amazes me sometimes how accurate the human body and mind is. Even a banger like me can hit the exact point on the pocket facing I'm aiming the OB at, and get the CB to land in a very small area for position. Granted, not all the time, but enough that it really is a feat to behold
I am surprised by: (though I shouldn't be)
1. it went over your head
2. you could ever think I was playing up to Pat - tho I know you can't read a little bit
I expect even PJ got a chuckle from the irony of that one
Any time you care to put your little money where your big mouth is on Maths contest,
Just let me know.
Dale
You agreed it was useless for practical purposes, and on top of that it doesn't answer the original question. So.... ya I guess add it to the list of useless information that I don't think is worth talking about. I think I made that very clear.
It responds to the original question. I don't believe there is a single answer to it.
Believe it or not, people have different ideas about what's worth talking about. For instance, I don't think what topics you like or dislike is very useful information.
pj
chgo
Your chart and everyone else's calculations don't answer the question, that's a fact. Therefore, at best, it's misleading and practically useless. My opinion is that this fact warrants the end of futile attempts at answering the question, because it can't be answered.
We all state opinions here. This isn't wikipedia. You clearly feel the need to explain to me what an opinion is, as if I'm not allowed to express them. This indicates that you feel like I attacked you or something, which I didn't.
There's no need to get so insecure and defensive just because I stated a reasonable opinion that you disagree with.