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dr_dave
02-23-2005, 04:13 PM
FYI, I just posted a bunch of new high-speed (super-slow-motion) video clips on my Illustrated Principles of Pool and Billiards (http://www.engr.colostate.edu/~dga/pool/) website. They are located under High-speed Video (HSV) Clips (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html) and the new clips are numbered HSV A.35 through HSV A.75. Here are a few conclusions that can be made from some of the clips:
<ul type="square"> The cue tip is in contact with the cue ball only for about 0.001 second for all types of shots, regardless of grip, speed, follow-through, and offset. Two exceptions are miscues and masse shots. This is in agreement with the Jacksonville Project results from 1999.

The type of grip (light vs. firm) and follow-through (good vs. a "punch" stroke with abbreviated follow-through) seems to have little effect on the amount of draw possible. The only things that matter seem to be the speed at impact and the amount of offset. Although, for me personally (and probably for many others), it is easier to generate tip speed and maintain offset accuracy with a light grip and good follow-through.

For a well-execute masse shot (see HSV A.60 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-60.htm)), the cue tip is in contact with the cue ball for much longer than 0.001 second (about 0.007 second) and the cue stick deflects quite a bit during impact.
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I will be writing a series of articles discussing the clips and various conclusions in detail in the near future. These articles will be posted on my website as soon as they are available.

I hope you enjoy and learn from the clips,
Dr. Dave

Billy_Bob
02-23-2005, 07:37 PM
What tip radius were you using for the draw shots (Nickel, dime, etc.)?

Also it is interesting to compare A.38 (7 ft. of draw) with A.41 (.5 ft. of draw). It seems that more of the tip is coming into contact with the ball with A.38.

Was a closed bridge -vs- an open bridge used with the follow shots?

And it would be interesting to somehow measure how much forward spin was placed on the cue ball for the follow shots. With the draw shots, I can compare the least amount of draw with the most amount of draw. Any way to do this with the follow shots? (Most amount of follow with least amount of follow.)

Rod
02-23-2005, 08:31 PM
The power break shot. I detect an above center hit, the cue deflects upward with forward c/b rotation. Possibly the breaker dropped their elbow causing this or a combination of both. In the last few frames the cue then goes straight through. Possibly the stroking arm started to rise dropping the front. Just an observation.

Rod

edatplaypool
02-23-2005, 09:26 PM
Dr Dave

From your description, its nice to see you've been able to confirm at least in your mind your preconceived notions regarding the elusive concept of "stroke." However from what you've described it's unlikely you wouold be able to convince anyone who really understands true scientific methods.

Who conducted the shots being videotaped? Have they ever been described as having a super stroke? If not, then you aren't seeing the actual technique that is behind a super stroke, so no wonder you conclude that it doesn't exist.

Take a person like Larry Nevel and take high speed video of him showing off his stroke. Then you will at least be seeing the phenomena that you are trying to prove doesn't exist.

dr_dave
02-24-2005, 09:36 AM
<blockquote><font class="small">Quote Billy_Bob:</font><hr>What tip radius were you using for the draw shots (Nickel, dime, etc.)?<hr /></blockquote>Nickel.
<blockquote><font class="small">Quote Billy_Bob:</font><hr>Also it is interesting to compare A.38 (7 ft. of draw) with A.41 (.5 ft. of draw). It seems that more of the tip is coming into contact with the ball with A.38.<hr /></blockquote>The big difference between these two shots is the amount of offset. The offset is much larger in HSV A.38 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-38.htm). I don't think it has much to do with the amount of tip in contact.
<blockquote><font class="small">Quote Billy_Bob:</font><hr>Was a closed bridge -vs- an open bridge used with the follow shots?<hr /></blockquote>An open bridge was used for all of the video clips.
<blockquote><font class="small">Quote Billy_Bob:</font><hr>And it would be interesting to somehow measure how much forward spin was placed on the cue ball for the follow shots. With the draw shots, I can compare the least amount of draw with the most amount of draw. Any way to do this with the follow shots? (Most amount of follow with least amount of follow.)<hr /></blockquote>Unfortunately, I did not try to measure the amount of follow, and this would be very difficult and tedious to measure from the videos. Sorry.

dr_dave
02-24-2005, 09:43 AM
<blockquote><font class="small">Quote Rod:</font><hr> The power break shot. I detect an above center hit, the cue deflects upward with forward c/b rotation. Possibly the breaker dropped their elbow causing this or a combination of both. In the last few frames the cue then goes straight through. Possibly the stroking arm started to rise dropping the front. Just an observation.<hr /></blockquote>
I admit that my power break stroke is probably not ideal. I do strive for slight follow so the cue ball will come to rest in the center of the table after recoiling back from the rack. Without slight follow, the cue ball heads up table. I also drop my elbow during my power break (mostly after cue ball impact). I strive for a straight "piston" stroke, trying to drive the cue stick straight into the rack, with a long, straight follow through. This might not be the best practice for most people, but for me it works fairly well. I have decent accuracy, good power, and decent cue ball control (most of the time).

Regards,
Dave

dr_dave
02-24-2005, 09:54 AM
<blockquote><font class="small">Quote edatplaypool:</font><hr>Who conducted the shots being videotaped?<hr /></blockquote>Me.
<blockquote><font class="small">Quote edatplaypool:</font><hr>Have they ever been described as having a super stroke?<hr /></blockquote>No, and I don't claim to have a "super stroke."
<blockquote><font class="small">Quote edatplaypool:</font><hr>If not, then you aren't seeing the actual technique that is behind a super stroke<hr /></blockquote>My purpose was to compare different stroke attributes, not to find the perfect stroke. I was able to vary the shot speed, offset, grip, and follow-through. That's all I was trying to do. Admittedley, a rigorous scientific study to find and characterize a "super stroke" would require many more subjects, many more trials, and lots of follow-on analysis. Maybe the next time I find 3 months of spare time and get full access to a high-speed camera, I will consider such a study. I did the best I could with the limited time and camera availability. I always wish I could do more.

tateuts
02-24-2005, 10:44 AM
Dave,

I don't know what the problem is, but on my computer the clips are very short, end abruptly, and will only play once (will not rewind). Are they supposed to be that way?

Chris

bluey2king
02-24-2005, 10:59 AM
Hello Dr. Dave; I just put on a phenolic tip on my break cue and the ball really seems to jump. It would be cool to see the differance in HSV. Did you notice the tips in your video deform?
I also noticed that on extream english that a lot of the contact seems to be on the outside of the tip. On the miscues this is the portion that seems to slip.
Thank You Dr. Dave, its Great to see this!

dr_dave
02-24-2005, 12:04 PM
<blockquote><font class="small">Quote tateuts:</font><hr>I don't know what the problem is, but on my computer the clips are very short, end abruptly, and will only play once (will not rewind). Are they supposed to be that way?<hr /></blockquote>
Most of the clips are about 30 seconds long. Is that what you have observed? From my main HSV page (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html), the clips should play inside the browser window. If you want to have more control over the video player (e.g., to change the size or whether or not clips loop), try using the alternative interface (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index_alt.html) instead.

dr_dave
02-24-2005, 12:12 PM
<blockquote><font class="small">Quote bluey2king:</font><hr>I just put on a phenolic tip on my break cue and the ball really seems to jump. It would be cool to see the differance in HSV.<hr /></blockquote>I will add this to my list of future things to shoot. Thanks for the suggestion.

<blockquote><font class="small">Quote bluey2king:</font><hr>Did you notice the tips in your video deform?<hr /></blockquote>This is really difficult to see with the limited frame rate, zoom, and resolution of the camera. Tip deformation occurs during the 1 millisecond of cue ball impact. HSV A.18 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-18.htm) offers one of the best views, but not much cue tip deformation is evident.
<blockquote><font class="small">Quote bluey2king:</font><hr>I also noticed that on extream english that a lot of the contact seems to be on the outside of the tip. On the miscues this is the portion that seems to slip.<hr /></blockquote>I agree with those observations. That's why it is important to chalk the outer, curved part of the cue tip. Chalk is not required in the center of the tip.

Regards,
Dr. Dave

BCgirl
02-24-2005, 10:19 PM
Dr Dave,

I found your videos quite interesting (particularly the ugly truth about miscues), although I have to say that I found myself looking at the cue motion in some of the shots, and wondering whether the visible cue tip deflection and the slightly odd trajectory of the cue and cue tip on some of the shots with extended follow through were both normal behaviour of the cue, or a slightly non-level cue and less than perfect technique. I had similar questions over the masse shot, where the CB seemed to jump quite a bit. If there are any doubts about the quality of the input (stroke), there has to be some doubt about the extent to which the observations are representative. It may be that I'm looking at secondary effects that the videos were not meant to illustrate, but I think it would be tremendously interesting to see a few draw/follow/masse shots executed by someone with a reknowned stroke (a Mike Massey, perhaps), as a baseline comparison.

As an aside, I did notice that on some videos, the playback timebase seemed to accelerate after contact. Is this a feature of the videos, or some issue with my media player?

BCgirl

dr_dave
02-25-2005, 09:12 AM
<blockquote><font class="small">Quote BCgirl:</font><hr>I found myself looking at the cue motion in some of the shots, and wondering whether the visible cue tip deflection and the slightly odd trajectory of the cue and cue tip on some of the shots with extended follow through were both normal behaviour of the cue, or a slightly non-level cue and less than perfect technique.<hr /></blockquote>
My follow-throughs were very straight. I think the effect you are seeing is the deflection and vibration of the cue stick that occurs immediately after impact. HSV A.5 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-5.htm) shows the effect fairly clearly.

<blockquote><font class="small">Quote BCgirl:</font><hr>I had similar questions over the masse shot, where the CB seemed to jump quite a bit.
I think it would be tremendously interesting to see a few draw/follow/masse shots executed by someone with a reknowned stroke (a Mike Massey, perhaps), as a baseline comparison.<hr /></blockquote>
I agree. The next time I have access to Mike or other pros I will try to do some filming. If Mike is out there listening (or if anyone knows Mike personally), feel free to contact me if you want to film some stuff with my camera.

<blockquote><font class="small">Quote BCgirl:</font><hr>As an aside, I did notice that on some videos, the playback timebase seemed to accelerate after contact. Is this a feature of the videos, or some issue with my media player?<hr /></blockquote>
Your media player is fine. I accelerated the playback during less interesting portions of the clips to reduce the sizes of the files. However, by looking at the "FWD" number in the top-left portion of the image, you can monitor the playback speed (e.g., FWD5 means 5 frames per second playback).

tateuts
02-26-2005, 04:08 PM
Dr. Dave,

My friend is a video game software publisher and programmer. I sent him to your site today. He bought a copy of everything. He loves those clips. My computer at work is having major problems with the clips, but the home PC plays them great.

Chris

dr_dave
02-26-2005, 05:25 PM
<blockquote><font class="small">Quote tateuts:</font><hr>My friend is a video game software publisher and programmer. I sent him to your site today. He bought a copy of everything. He loves those clips.<hr /></blockquote>Thanks for the referral. Word of mouth is important in the pool world.
<blockquote><font class="small">Quote tateuts:</font><hr>My computer at work is having major problems with the clips, but the home PC plays them great.<hr /></blockquote>If you figure out what the problem is at work, please let us know so others will know the fix.

Regards,
Dr. Dave

Bob_Jewett
03-02-2005, 11:08 AM
I have bundled three BD articles about the Jacksonville Project into a PDF on the SFBA website: http://www.sfbilliards.com/jax_bd150.pdf

Included there is a speed/time analysis of a typical shot which shows the nearly instantaneous slowing of the stick at impact and the subsequent partial recovery of stick speed.

dr_dave
03-02-2005, 02:59 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> I have bundled three BD articles about the Jacksonville Project into a PDF on the SFBA website: http://www.sfbilliards.com/jax_bd150.pdf
<hr /></blockquote>
Bob,

Thanks for posting this. It's a great resource to have available online. Maybe we can get some of the video clips posted as we have discussed. I'm sure many people would be interested in seeing them.

Regards,
Dave

dr_dave
03-02-2005, 03:34 PM
FYI,

I just added a very cool clip (HSV A.76 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-76.htm)) to my high-speed video website (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html). It shows various super-slow-motion carom, jump, and kick shots filmed at 2000 frames/sec with a very high resolution, full color, high-speed camera. The clip also includes infrared footage showing how temperatures change dramatically on the ball and cloth during various types of shots. The clip is awesome. Check it out.

The video was provided by the Billiard SportKlub Union out of Austria (www.bskunion.at (http://www.bskunion.at/)).

Regards,
Dr. Dave

MrLucky
03-02-2005, 03:59 PM
This has been a amazing read of your PDF and fantastic videos ! much thanks for posting! /ccboard/images/graemlins/smile.gifI've learned much from both and this not only helps with shots but also in my knowledge of cues! /ccboard/images/graemlins/cool.gif

PQQLK9
03-02-2005, 04:02 PM
Awesome Dave /ccboard/images/graemlins/smile.gif nice music also.

dr_dave
03-02-2005, 04:13 PM
<blockquote><font class="small">Quote MrLucky:</font><hr> This has been a amazing read of your PDF and fantastic videos ! much thanks for posting! /ccboard/images/graemlins/smile.gifI've learned much from both and this not only helps with shots but also in my knowledge of cues! /ccboard/images/graemlins/cool.gif <hr /></blockquote>
You are very welcome. Thanks for the positive feedback.
Dave

dr_dave
03-02-2005, 04:36 PM
<blockquote><font class="small">Quote PQQLK9:</font><hr> Awesome Dave /ccboard/images/graemlins/smile.gif nice music also.<hr /></blockquote>
I can't take credit for the video or the music. The Austrian group provided both.

I like the music also. /ccboard/images/graemlins/smile.gif

dr_dave
03-04-2005, 01:42 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> I have bundled three BD articles about the Jacksonville Project into a PDF on the SFBA website: http://www.sfbilliards.com/jax_bd150.pdf

Included there is a speed/time analysis of a typical shot which shows the nearly instantaneous slowing of the stick at impact and the subsequent partial recovery of stick speed. <hr /></blockquote>
Bob,

It seems like you have lots of good resources like these on your website. Is there a way to view or see a list of all the resources you have posted? When I visit your website, I don't see any way to find or search for the resources. Do you have a list and description of links somewhere that you can share with us?

Thanks,
Dave

Bob_Jewett
03-04-2005, 03:53 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> ... Do you have a list and description of links somewhere that you can share with us? ... <hr /></blockquote>
Well, there is the description of links on the SFBA misc links page: http://www.sfbilliards.com/misc.htm It takes less than a minute to read through the descriptions of the links, and only a few days to look at all the links.

dr_dave
03-04-2005, 03:58 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr> ... Do you have a list and description of links somewhere that you can share with us? ... <hr /></blockquote>
Well, there is the description of links on the SFBA misc links page: http://www.sfbilliards.com/misc.htm It takes less than a minute to read through the descriptions of the links, and only a few days to look at all the links. <hr /></blockquote>
Thanks. That's what I was looking for.