curving an object ball....

dr_dave said:
John Brumback said:
https://www.youtube.com/watch?v=Ls0PcLQ4TIo
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John,

Thanks for posting this.
...
It looks like you did get a small amount of post-rebound OB curve. It wasn't really necessary to avoid the obstacle ball, but it certainly is noticeable. As I promised, I will attempt to get similar action on my equipment (and if it doesn't work, I try some tables at the pool hall).
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Based on the fact that the camera is moving in John's video, and based on the issues brought up in my recent video, I am now not confident that John's video is convincing evidence of OB curving (i.e., I retract my quoted statement). I still believe it is possible, but I still haven't seen convincing proof.

Regards,
Dave
 
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Dave,

If banking lessons are being offered at the same hall by John Brumback & a Science Guy with pool for a hobby...

I'm going to John Brumback's table.

Regards,
Rick
 
Still tugging on Superman's cape I see, lol. All I know is that JB's technique is worth studying and worth emulating. I guess it's possible that I have perceived these shots as curving when they are not. I played some bank pool this past weekend and i am certain that i saw my opponent curve the object ball. Nevertheless, the only important thing is knowing how to hit 'em and doing it enough to feel how to do it consistently.

Even if it is conclusively proved that an object ball can not curve, I still know that JB's approach to banking is the best. Your video proves that angle in/ out is not the best banking technique. Hitting with speed and holding up the object ball is more important to understand, imo.

One thing that John does with appalling consistency is drilling tough bank shots. Bend or no bend ultimately does not matter. I want to know what John knows and I want to try to gain his ability to sense and feel the shot.

I would be real curious just how how far up the rail that your shot can be made. Put another way, how much can you "hold" the object ball?

Thanks again for trying to get us all to understand our game better.
 
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Thinking more about your shot, can you try this banking off the short rail going to the corner pocket? The extra travel distance might aid in perceiving what is possible with this type of shot. Just a thought.
 
jalapus logan said:
I guess it's possible that I have perceived these shots as curving when they are not.
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I'm guilty of that also, especially with the Freddy clips I included. I was sure those were being bent the first time I saw them. Also, when filming for the video, I was "sure" some of the shots bent when I hit them, especially the one with the "sticky" CB. I was confident that one bent ... until I studied the video carefully later.

jalapus logan said:
Nevertheless, the only important thing is knowing how to hit 'em and doing it enough to feel how to do it consistently.
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I couldn't agree more. Stiffing/twisting/shorting a bank with speed and/or spin is a very important technique.

jalapus logan said:
I would be real curious just how how far up the rail that your shot can be made. Put another way, how much can you "hold" the object ball?
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It depends on conditions. I'm sure I could hold much shorter in a humid environment (... Colorado is dry), especially on a dirty table with dirty balls.

jalapus logan said:
Thanks again for trying to get us all to understand our game better.
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You're welcome.

I am to swerve,
Dave
 
jalapus logan said:
Thinking more about your shot, can you try this banking off the short rail going to the corner pocket? The extra travel distance might aid in perceiving what is possible with this type of shot. Just a thought.
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I have tried long, straight-back banks also ... they didn't bend either.

FYI, I chose the Freddy shot since others had mentioned it, and since it is very clear how Freddy hits it on the video, and since it "seems" to curve a lot ... even though it doesn't.

Regards,
Dave
 
All of this has reminded me that I need to get.my hands on one of John's banking DVDs. My bank game needs some work no doubt. Thanks to JB and to Dr Dave for finally ignighting this particular fire.
 
jalapus logan said:
All of this has reminded me that I need to get.my hands on one of John's banking DVDs. My bank game needs some work no doubt. Thanks to JB and to Dr Dave for finally ignighting this particular fire.
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I can't believe how much easier it is (for me) to bank if you use JB's methods as shown in the first DVD.

No wonder he's so good, he does it the easy way. :)
 
lfigueroa said:
That's really nice work, Dave.

Lou Figueroa
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Thanks Lou.

I'm surprised more people haven't commented on the video. Filming it was certainly an eye-opening experience for me. At first, I was very disappointed that I didn't see any bend in the OB path with any of the shots on any of the equipment or conditions. But after I found logical explanations for why people might think balls are bending (including me at first), I was in a happier place. I still think it is possible to bend a bank (since the cushion nose can impart topspin parallel to the rail and masse spin, both of which can curve the OB's path), but I think it would require unique conditions. I think the main reason why the bend is not occurring is that any topspin or masse spin imparted to the ball during cushion nose compression has an effect (and dissipates) only when the OB interacts with the bed of the table during the first hop caused by the cushion nose pushing the OB down. Then the OB heads in a straight line (although, the spin imparted by the cushion does contribute to shortening the bank).

Regards,
Dave
 
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Thanks for the video dr. dave. A couple of comments:

1. Part of the illusion of curving might come from the fact that often in those shots right before it goes into the pocket it hits the short rail and then goes into the pocket to the right (from camera perspective). When it’s looked at quickly, that might make it seem like it’s bending.

2. The object ball is spinning with the english it picks up off the rail, which may also contribute to the illusion. And it is spinning close to the direction you would expect for the appropriate masse effect.

3. The bouncing off the table should make the ball look like it’s curving long rather than short (i.e., from our camera perspective, to the left rather than to the right). You're right that it does distort the path in general, but it shouldn't account for the appearance of this particular curve.

4. Question: We know that it’s easy to get a kicked cue ball to bend forward or pull backward, if it’s rolling or back-spinning when it comes off the rail. Shouldn’t it be easy to get a banked ball to show the same forward bend as a kicked rolling cue ball? I would think it would help if it’s banked pretty wide, like 4-5 diamonds. The trick is to get a banked object ball to pull back like a drawn cue ball pulls back. That’s what Freddy appears to be trying to do, and that's what seems like it would be very difficult to do. But do you agree that it should be possible to curve a banked object ball long?
 
BRussell said:
Thanks for the video dr. dave. A couple of comments:

1. Part of the illusion of curving might come from the fact that often in those shots right before it goes into the pocket it hits the short rail and then goes into the pocket to the right (from camera perspective). When it’s looked at quickly, that might make it seem like it’s bending.

2. The object ball is spinning with the english it picks up off the rail, which may also contribute to the illusion. And it is spinning close to the direction you would expect for the appropriate masse effect.

3. The bouncing off the table should make the ball look like it’s curving long rather than short (i.e., from our camera perspective, to the left rather than to the right). You're right that it does distort the path in general, but it shouldn't account for the appearance of this particular curve.
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Excellent observations!


BRussell said:
4. Question: We know that it’s easy to get a kicked cue ball to bend forward or pull backward, if it’s rolling or back-spinning when it comes off the rail. Shouldn’t it be easy to get a banked ball to show the same forward bend as a kicked rolling cue ball?
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Agreed. It is very easy to bend a bank shot forward in the long direction when the OB rolls into the rail with topspin (due to slower speed and/or greater distance to the rail). This effect is the same as with the rolling and bending kick shots demonstrated in NV H.2 - Bending, Twisting, and Stiffening Kick and Bank Shots.

BRussell said:
The trick is to get a banked object ball to pull back like a drawn cue ball pulls back. That’s what Freddy appears to be trying to do, and that's what seems like it would be very difficult to do.
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Exactly. This was the point of the video ... to try to bend a bank backward in the short direction. Again, it is easy to bend it forward. In fact, the main reason why fast speed is used by top bank-pool players is to limit bend forward, which varies too much with shot angle, speed, and conditions. For more info, see advantages of fast-speed banks.

Regards,
Dave
 
Great video Dave.. I'm a die hard banker and always thought the ball was bending.. Your slow motion video has me second guessing myself.
 
MOJOE said:
Great video Dave.. I'm a die hard banker and always thought the ball was bending.. Your slow motion video has me second guessing myself.
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Thanks.

I have to admit that I thought Freddy's bank was bending at first. I also could have sworn some of the shots I hit during filming were bending ... until I studied the video carefully after.

Regards,
Dave
 
BRussell said:
3. The bouncing off the table should make the ball look like it’s curving long rather than short (i.e., from our camera perspective, to the left rather than to the right). You're right that it does distort the path in general, but it shouldn't account for the appearance of this particular curve.
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Actually, I do think the perspective distortion created by the large initial hop could lead to an incorrect perception that the OB is curving short. When the OB is in the air, it appears to be further up-table, heading directly toward the obstacle ball. But when it lands, it is clearly on a line further down table which clears the obstacle. I think that can visually mislead something into think the ball is curving short around the obstacle ball. Watch the end of the video again, where I analyzed Freddy's shots, with this in mind.

Catch you later,
Dave
 
I said this once and will say it again, a repost for the good Dr.

Agreed, fantastic body of work and enormous amount of dedication.
If billiards had an Honor Society Dr. Dave leads the pack.


Sincerely: SS
 
Somebody sent me the following observation via e-mail. I think it might be an additional contributing factor for why people might think why fast-speed banks bend short.

from a recent e-mail:

Another likely reason for the common illusion of OBs bending back is that we probably subconsciously compare a straight rebound with the usual tendency to bend forward. Kind of like when you’ve been in a moving vehicle watching the scenery go by – when the vehicle stops the scenery looks like it’s going forward for a second.
 
dr_dave said:
Actually, I do think the perspective distortion created by the large initial hop could lead to an incorrect perception that the OB is curving short. When the OB is in the air, it appears to be further up-table, heading directly toward the obstacle ball. But when it lands, it is clearly on a line further down table which clears the obstacle. I think that can visually mislead something into think the ball is curving short around the obstacle ball. Watch the end of the video again, where I analyzed Freddy's shots, with this in mind.

Catch you later,
Dave
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I see - what's interesting to me is that that's actually a forward curve instead of a backward curve, which is the curve that I see.
 
BRussell said:
dr_dave said:
Actually, I do think the perspective distortion created by the large initial hop could lead to an incorrect perception that the OB is curving short. When the OB is in the air, it appears to be further up-table, heading directly toward the obstacle ball. But when it lands, it is clearly on a line further down table which clears the obstacle. I think that can visually mislead something into think the ball is curving short around the obstacle ball. Watch the end of the video again, where I analyzed Freddy's shots, with this in mind.
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I see - what's interesting to me is that that's actually a forward curve instead of a backward curve, which is the curve that I see.
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Actually, what I was attempting to describe is a perceived backward curve. The ball rising up into the air and apparently moving more up-table (due to camera perspective) could be perceived as a forward curve. But as the ball comes down, it apparently moves more down-table than it actually does (again, due to camera perspective) before straightening out to the final direction past the obstacle. This could be perceived as a backward curve. I think this effect is the one that is most responsible for fooling people into thinking the ball is curving short (e.g., in the Freddy video).

Does that make more sense now?

Regards,
Dave
 
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