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dr_dave
07-26-2005, 02:52 PM
FYI,

I finished editing all of the video I shot last week with the high-speed camera. The results are posted in clips HSV A.77-A.127 in the high-speed-video portion of my website (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html). Check them out.

Thanks to many of you for providing ideas for the shoot. I wasn't able to accommodate everybody's requests, but I got most of the list done. I'll post some additional messages under this thread with some preliminary analysis results for discussion. Also, I hope to write an article or two for BD in the near future.

Enjoy,
Dr. Dave

PS: I want to thank Dave Gross, Chris McDaniel, and Mike Hellmer for helping with the shoot. They are all top notch players that live in the Fort Collins area. Mike owns "MatchUps," a local pool hall. I shot some of the video on my home table, and the others at MatchUps.

dr_dave
07-26-2005, 03:02 PM
Clips HSV A.77-A.81 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html) show close-ups of cue tip impact for various hardness tips and various speeds. Here are some conclusions:

- most contact times (i.e., for most tips and most speeds) are very close to a thousandth of a second (0.001 sec).

- a soft tip at slow speed has a longer contact time (about 0.002 sec), but still extremely small.

- a very hard tip (phenolic) at fast speed has a shorter contact time (about 0.0005 sec).

- the contact time decreases slightly for faster speeds, but not by much.

- chalk does not stay on hard tips very well at impact (see the blue clouds that separate from the tips in the videos).

Regards,
Dr. Dave

dr_dave
07-26-2005, 03:27 PM
Clips HSV A.82-A.84 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html) show English transfer and throw for various offsets ("tips" of English) and speeds. The results agree with the analysis and plots in TP A.14 (http://www.engr.colostate.edu/~dga/pool/technical_proofs/new/TP_A-14.pdf):

- English transfer and throw are directly related (because they both result from the same friction force).

- there is less throw at higher speeds.

- the amount of throw does not vary very much with the amount of offset.

- the largest throw occurred at the slowest speed with a medium amount of offset.

- The amount of throw varied from 4 degrees to 7 degrees over all speeds and offsets.

Regards,
Dr. Dave

dr_dave
07-26-2005, 03:31 PM
FYI,

My August '05 BD instructional article (http://www.engr.colostate.edu/~dga/pool/bd_articles/index.html) presents some background information on high-speed video work done by others, describes the process and equipment, and describes some interesting results. Check it out if you are interested.

Dr. Dave

Billy_Bob
07-26-2005, 03:47 PM
Boy have you been busy! Lots of neat stuff there. I really like the break shot - would be something interesting to explore further? And the masse' shot is cool - another thing to explore further - different angles maybe?

I think I learned why I need to chalk my phenolic jump cue so much - all the chalk flies off with each hit!

And Predator shafts, gear action between balls, not to mention the kick shots hitting the rail. All very interesting stuff.

I think you have about two years worth of articles from just this last batch of videos alone? It will be interesting to read further about this when you "write 'em up".

Thanks...

dr_dave
07-26-2005, 04:06 PM
FYI,

Clips HSV A.98-A.109 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html) show limited evidence on the effects of tip hardness, offset, and speed on English spin and squirt. Unfortunately, different shafts were used with the different tips, so it is dangerous making too many conclusions concerning these influences. However, the following seems to be true:

- squirt is larger for larger offsets.

- squirt is larger (anywhere from 20% to 50%) for faster speeds. This is consistent with the anecdotal evidence in video demo NV A.17 (http://www.engr.colostate.edu/~dga/pool/normal_videos/new/NVA-17.htm).

- squirt is smaller for low squirt cues (the Predator 314 and Z shafts). The squirt for the Predator Z shaft (better than the 314) was about 30% less than the squirt for the other cues tested, on average.

- tip hardness, shaft type, or speed does not appear to have much of an effect on the amount of spin generated for different offsets.

Regards,
Dr. Dave

dr_dave
07-26-2005, 04:13 PM
Clips HSV A.110-A.115 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html) show the effects of speed, cue stick elevation, and follow-through on double-hit avoidance for a chalk-width gap between the CB and OB. Unfortunately, clips A.110-A.112 and A.113-A.115 are from different viewpoints and were shot by different shooters with different amounts of follow-through, but the results are interesting nonetheless. Notice that the cue stick nudges the CB in mid air (i.e., the shot is a foul) in the 3rd (fast) stroke of A.112. This one is tough to call even with the high-speed camera.

Dr. Dave

dr_dave
07-26-2005, 04:25 PM
Clips HSV A.117-A.120 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html) show the different reactions of a polished vs. non-polished ball rebounding off a cushion with different vertical plane spins (follow, stun, draw) and speeds. One thing to notice is that the polished ball retains topspin (bottom spin after rebound) a little better. It is also interesting to note that bottom spin gets removed (stunned) in most cases (because the ball is being driven into the table by the cushion, creating more friction).

Regards,
Dr. Dave

dr_dave
07-26-2005, 04:33 PM
HSV A.123 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-123.htm) shows CB hop effects during a power break. Notice that the CB does not hop with draw. The CB hops with follow partly due a climbing effect and partly due to CB skipping due to follow squirt into the table (see HSV A.124 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-124.htm)), especially in the last shot where both the CB and 1-ball hop.

Dr. Dave

dr_dave
07-26-2005, 04:44 PM
Unfortunately, I was not able to observe deformation or contact time during ball-to-ball collisions. The amount of ball deformation is much too small to see with the equipment I have. (Per the data in Marlow's book, the amount of deformation is only about a hundredth of an inch [0.01 in], even for high-speed collisions.) Also, the contact time is much too short to measure, even with high-speed video equipment. (Per Marlow, ball-to-ball contact times are only a few ten-thousandths of a second [e.g., 0.0003 sec].) The best I could do to try to visualize these effects is shown in HSV A.125 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-125.htm).

Dr. Dave

dr_dave
07-27-2005, 01:03 PM
Billy_Bob,

Thanks for the comments. I'm glad I'm not the only person that gets excited about super-slow-motion video. I'm surprised others have not posted comments or started some discussion. I think there's lots of good information in the clips.

Regards,
Dave

<blockquote><font class="small">Quote Billy_Bob:</font><hr> Boy have you been busy! Lots of neat stuff there. I really like the break shot - would be something interesting to explore further? And the masse' shot is cool - another thing to explore further - different angles maybe?

I think I learned why I need to chalk my phenolic jump cue so much - all the chalk flies off with each hit!

And Predator shafts, gear action between balls, not to mention the kick shots hitting the rail. All very interesting stuff.

I think you have about two years worth of articles from just this last batch of videos alone? It will be interesting to read further about this when you "write 'em up".

Thanks... <hr /></blockquote>

Rod
07-27-2005, 11:10 PM
<blockquote><font class="small">Quote dr_dave:</font><hr>

Thanks for the comments. I'm glad I'm not the only person that gets excited about super-slow-motion video. I'm surprised others have not posted comments or started some discussion. I think there's lots of good information in the clips.

Regards,
Dave

<hr /></blockquote>

Well since you asked, LOL I viewed a few the other night. It appeared HSV 4.10 thru 4.13 all was hit rail first. If I recall correct 4.13 was early but hit considerably more firm than the rest. You can see how much the rail is compressed.

If I was planning a route with the c/b I surely wouldn't have liked the direction. Just an observation.

Rod

dr_dave
07-28-2005, 07:27 AM
<blockquote><font class="small">Quote Rod:</font><hr>It appeared HSV 4.10 thru 4.13 all was hit rail first. If I recall correct 4.13 was early but hit considerably more firm than the rest. You can see how much the rail is compressed.<hr /></blockquote>
That's all true. The purpose for those clips was to show several possible reactions of rail-first, running English shots.

<blockquote><font class="small">Quote Rod:</font><hr>If I was planning a route with the c/b I surely wouldn't have liked the direction. Just an observation.<hr /></blockquote>
I'm not sure what point you are making here. I assume you mean that to achieve a desired cue ball direction, you might want to hit the OB first or the OB and rail at the same time (provided the OB is close enough to the corner pocket), or use different English and/or speed. Am I missing your point?

Regards,
Dave

BigRigTom
07-28-2005, 08:44 AM
Dr. Dave,
Great videos!
I just watched!
HSV A.123 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-123.htm)
....AND ....
Am I seeing 3 breaks in the order of draw then follow then skip?
And since I only see the cue ball and the one ball...
Are you hitting a rack of 15 balls?
Lastly ...how do you make the cue ball skip into the rack?
I thought the skip came from a high hit on the cue ball in and attempt to create follow but sounds like you just jacked up the butt of the cue similar to a jump shot...is that correct?

dr_dave
07-28-2005, 08:59 AM
<blockquote><font class="small">Quote BigRigTom:</font><hr> Dr. Dave,
Great videos!
I just watched!
HSV A.123 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-123.htm)
....AND ....
Am I seeing 3 breaks in the order of draw then follow then skip?<hr /></blockquote>
Yes.
<blockquote><font class="small">Quote BigRigTom:</font><hr>And since I only see the cue ball and the one ball...
Are you hitting a rack of 15 balls?<hr /></blockquote>
Nope ... 9-ball rack each time.
<blockquote><font class="small">Quote BigRigTom:</font><hr>Lastly ...how do you make the cue ball skip into the rack?<hr /></blockquote>
You don't need to do anything special to make it skip. With any cue stick elevation (and because of the height of the rails, it is impossible to not have some elevation with a break shot), the CB will skip some (more at higher speeds), unless you hit just the right amount below center to have the upward "squirt" cancel the downward component of speed. Also, for any hard follow shot, the CB can skip quite a bit on its own (e.g., see HSV A.124 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-124.htm) showing the CB skip over a stack of three dimes with a fairly level stroke).
<blockquote><font class="small">Quote BigRigTom:</font><hr>I thought the skip came from a high hit on the cue ball in and attempt to create follow but sounds like you just jacked up the butt of the cue similar to a jump shot...is that correct?<hr /></blockquote>
The cue stick was not jacked up. It was a normal power break shot performed by a fairly good shooter (Mike Hellmer).

Regards,
Dave

Billy_Bob
07-28-2005, 09:11 AM
What is skip?

I know if you hit down on the cue ball, it will become airborne, then is in the air - not touching the cloth at time of impact, then this makes the cue ball bounce "up".

Is "skip" anything to do with this?

Rod
07-28-2005, 09:18 AM
[ QUOTE ]
I'm not sure what point you are making here. I assume you mean that to achieve a desired cue ball direction, you might want to hit the OB first or the OB and rail at the same time <hr /></blockquote>

Yes that's what I mean. I was a bit confused though since there isn't any mention in the 4.10 footage of hitting rail first. It only says with running english.

Rod

Rod
07-28-2005, 10:38 AM
[ QUOTE ]
You don't need to do anything special to make it skip. With any cue stick elevation (and because of the height of the rails, it is impossible to not have some elevation <hr /></blockquote>

I've said for a long time pool is played in the air, more than most believe. Even showed it with coins stacked on top of each other. Although people don't fully understand the concept, it's just a mini jump shot without even trying.

At upper levels of play it can be important to know the c/b is airborne. Many failed shots are for this reason.

Rod

dr_dave
07-28-2005, 12:59 PM
<blockquote><font class="small">Quote Billy_Bob:</font><hr> What is skip?

I know if you hit down on the cue ball, it will become airborne, then is in the air - not touching the cloth at time of impact, then this makes the cue ball bounce "up".

Is "skip" anything to do with this?<hr /></blockquote>
You are correct. By "skip," I mean a mini jump or a secondary "mini" jump (if the CB returns to the table and bounces again). HSV A.124 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-124.htm) shows an example of the initial mini jump due to a hard follow shot.

Regards,
Dave

dr_dave
07-28-2005, 01:07 PM
<blockquote><font class="small">Quote Rod:</font><hr><blockquote><font class="small">Quote dr_dave:</font><hr>I'm not sure what point you are making here. I assume you mean that to achieve a desired cue ball direction, you might want to hit the OB first or the OB and rail at the same time<hr /></blockquote>
Yes that's what I mean. I was a bit confused though since there isn't any mention in the 4.10 footage of hitting rail first. It only says with running english.<hr /></blockquote>
Rod,

Thanks for the clarification ... now I understand.

The main purpose for HSV 4.11-4.13 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html) is to show extreme/exaggerated examples of HSV 4.10 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/HSV4-10.htm) to support discussion and illustrations in my book. Without descriptions, explanations, and illustrations, the clips alone often don't tell the whole story. Sorry about that (but that's what the book is for).

Regards,
Dave

dr_dave
07-28-2005, 01:14 PM
<blockquote><font class="small">Quote Rod:</font><hr><blockquote><font class="small">Quote dr_dave:</font><hr>You don't need to do anything special to make it skip. With any cue stick elevation (and because of the height of the rails, it is impossible to not have some elevation <hr /></blockquote>
I've said for a long time pool is played in the air, more than most believe. Even showed it with coins stacked on top of each other. Although people don't fully understand the concept, it's just a mini jump shot without even trying.<hr /></blockquote>
FYI, HSV A.124 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-124.htm) shows this in super slow motion (although, the clarity and focus are not great).
<blockquote><font class="small">Quote Rod:</font><hr>At upper levels of play it can be important to know the c/b is airborne. Many failed shots are for this reason.<hr /></blockquote>
Now I'm curious. Some examples I can think of are:
- the cut angle is changed due to the higher contact point on the CB.
- the CB and OB will jump after impact, possibly resulting in balls leaving the table.
Do you have other examples in mind?

Thanks,
Dave

Jal
07-28-2005, 03:25 PM
<blockquote><font class="small">Quote dr_dave:</font><hr>...
I'm surprised others have not posted comments or started some discussion. I think there's lots of good information in the clips.<hr /></blockquote>

Sorry Dr. Dave. I'm sure there's been much more interest than has been indicated thus far. It takes a while (especially for those of us on dialup) to absorb it all.

I found the shots with the cueball frozen to the object ball particularly interesting. Bob Jewett's interference system is predicated on the fact that the cueball and object ball will travel with virtually the same speed down the initial line of centers direction (the component of the cueball's velocity that is). Your videos show them doing just that for the entire span of cue stick approach angles.

I also thought that for the straight on kick shots into the rail, some draw would be retained. But it's clear from the videos that this is not the case.

I wonder if there is any way to view them frame by frame? I know how to save the temp files but is there a viewer that will allow you to do this (frame by frame) with the .wmv format?

Jim

bluey2king
07-28-2005, 04:11 PM
Hello Dr Dave
I have a couple of Q's after watching your videos.
What tip was on your Predator Z and 314 shafts?
Is your conclusion on tips pick the one that feels best to the player because the difference is small? (exclude super hard tips)
Did you come to any conclusions about aiming to correct for squirt? 1/2 tip offset = x on a two foot shot?
It look to me that the CB squirts left then tracks staight. Is that correct?
Last one (for Now *S*) Have you ever tried another laminated shaft?
Thank You for sharing I can see that this is a lot of work!! I love seeing what happens in slow motion.

Voodoo Daddy
07-28-2005, 04:53 PM
Someone hand me a bucket

caedos
07-28-2005, 09:07 PM
Is there significant difference in the amount of squirt using a hard tip vs. a soft tip, given all other conditions remain the same?

Rod
07-29-2005, 12:38 AM
<blockquote><font class="small">Quote dr_dave:</font><hr>
Now I'm curious. Some examples I can think of are:
- the cut angle is changed due to the higher contact point on the CB.
- the CB and OB will jump after impact, possibly resulting in balls leaving the table.
Do you have other examples in mind?

Thanks,
Dave <hr /></blockquote>

Well sure but I'm thinking more about how/when the c/b reacts. The o/b may jump to a degree but that may not be important in this context. It's only important if your focus is on the o/b (making it do something other than roll). It's what you want the c/b to do.

Knowing it may/will hop can change your plans on how you shoot a shot. Of course speed, cue angle if any, always plays a part. If you don't know then you get whatever you did. You may want it to react right away (keep it on the table) or you may want to delay the action. Hence you build in a hop. These shots are mild to wild but some certainly are part of everyday pool. Think about it. Or, look it up in your training/instruction manuals. LOL

Rod

dr_dave
07-29-2005, 08:34 AM
<blockquote><font class="small">Quote Voodoo Daddy:</font><hr> Someone hand me a bucket <hr /></blockquote>
I hope you are just joking. If not, I take great offense at your subject and message.

I have worked my A** off this past week to shoot the videos, do the analysis, and post the results on this forum. If you think I did this because it would sell a few extra books, you have a twisted mind (IMHO). Do the math. The hourly rate is not that good.

Disappointed,
Dave /ccboard/images/graemlins/confused.gif

dr_dave
07-29-2005, 08:44 AM
<blockquote><font class="small">Quote caedos:</font><hr> Is there significant difference in the amount of squirt using a hard tip vs. a soft tip, given all other conditions remain the same? <hr /></blockquote>
Unfortunately, not all conditions remained the same in clips HSV A.98-A.109 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index_alt.html). Each tip was on a different shaft, and the shafts were all different. However, from the data I have, and from my intuition (based on my understanding of friction and its effect on squirt), I would guess that squirt might be slightly smaller for a softer tip (especially at slower speeds).

Sorry I don't have better data or explanations. Maybe others out there can share what they know.

Regards,
Dave

dr_dave
07-29-2005, 11:06 AM
<blockquote><font class="small">Quote Jal:</font><hr>I found the shots with the cueball frozen to the object ball particularly interesting. Bob Jewett's interference system is predicated on the fact that the cueball and object ball will travel with virtually the same speed down the initial line of centers direction (the component of the cueball's velocity that is). Your videos show them doing just that for the entire span of cue stick approach angles. <hr /></blockquote>
Jim,

I was also impressed by how closely the video results in HSV A.97 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-97.htm) agree with Bob's method. I was so impressed, I decided to do a detailed analysis and comparison. See my posting on this topic (http://www.billiardsdigest.com/ccboard/showthreaded.php?Cat=&amp;Board=ccb&amp;Number=201944&amp;page =0&amp;view=collapsed&amp;sb=5&amp;o=&amp;fpart=&amp;vc=) for more information.

I was not aware that Bob's method had a physical basis. I just thought it was a heuristic geometric method that happened to match the physics fairly closely. If Bob is out there listening, maybe he can expand. (Or even better, maybe he can post his original BD article so we can read the original source.)

Regards,
Dave

dr_dave
07-29-2005, 11:22 AM
<blockquote><font class="small">Quote Jal:</font><hr>I also thought that for the straight on kick shots into the rail, some draw would be retained. But it's clear from the videos that this is not the case.<hr /></blockquote>
I was also a little surprised by this, especially for the polished ball in HSV A.119 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-119.htm) and HSV A.120 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-120.htm). However, it makes sense if you think about the directions of the friction forces from both the cushion and the table cloth as the cushion compresses and drives the ball down. Also, as the ball comes back up and out of the cushion, maybe the elastic rebound forces also tend to reverse the spin.

Regards,
Dave

dr_dave
07-29-2005, 11:30 AM
<blockquote><font class="small">Quote Jal:</font><hr>I wonder if there is any way to view them frame by frame? I know how to save the temp files but is there a viewer that will allow you to do this (frame by frame) with the .wmv format?<hr /></blockquote>
The only player I've used is the Windows Media Player; and unfortunately, I don't think it can advance a WMV file frame by frame. This is also very disappointing to me, because it seems like it should be easy to do in software (by the Microsoft programmers). I kind of cheat it by pressing CTRL-P on the keyboard twice, quickly, to start and stop the clip. I found that this is much more reliable than clicking the mouse button on the player's pause button.

Does anybody know of any better solutions?

Dave

dr_dave
07-29-2005, 12:35 PM
<blockquote><font class="small">Quote bluey2king:</font><hr>What tip was on your Predator Z and 314 shafts?<hr /></blockquote>
LePro Medium-Hard tips.

<blockquote><font class="small">Quote bluey2king:</font><hr>Is your conclusion on tips pick the one that feels best to the player because the difference is small? (exclude super hard tips)<hr /></blockquote>
Sounds good to me.

<blockquote><font class="small">Quote bluey2king:</font><hr>Did you come to any conclusions about aiming to correct for squirt? 1/2 tip offset = x on a two foot shot?<hr /></blockquote>
You need to experiment with a given shaft (and tip) and bridge length to know how much to adjust. Also, speed can be a factor (see my posting on speed effects (http://www.billiardsdigest.com/ccboard/showthreaded.php?Cat=&amp;Board=ccb&amp;Number=201674&amp;page =0&amp;view=collapsed&amp;sb=5&amp;o=&amp;vc=1)), which with you should also experiment.
<blockquote><font class="small">Quote bluey2king:</font><hr>It look to me that the CB squirts left then tracks staight. Is that correct?<hr /></blockquote>
Yes ... at first. Then curve (swerve) can take place back in the opposite direction. The amount of curve depends on cue stick elevation and the amount of bottom and side English. How soon the swerve takes place depends on shot speed.
<blockquote><font class="small">Quote bluey2king:</font><hr>Last one (for Now *S*) Have you ever tried another laminated shaft?<hr /></blockquote>
Not to my knowledge.
<blockquote><font class="small">Quote bluey2king:</font><hr>Thank You for sharing I can see that this is a lot of work!! I love seeing what happens in slow motion.<hr /></blockquote>
You're very welcome. I also love seeing it, which makes the hard work not seem so hard after all.

Regards,
Dave

Bob_Jewett
07-29-2005, 01:51 PM
<blockquote><font class="small">Quote dr_dave:</font><hr>.. I was not aware that Bob's method had a physical basis. I just thought it was a heuristic geometric method that happened to match the physics fairly closely. ... <hr /></blockquote>
I think that if you analyze it as a soft tip and hard balls, the 2:1 tangent falls out fairly easily. I think the main clue is that the momentum of the two balls along the initial line of centers is equal.

dr_dave
07-29-2005, 02:42 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr>.. I was not aware that Bob's method had a physical basis. I just thought it was a heuristic geometric method that happened to match the physics fairly closely. ... <hr /></blockquote>
I think that if you analyze it as a soft tip and hard balls, the 2:1 tangent falls out fairly easily.<hr /></blockquote>
What are the assumptions made in such an analysis? For example, is it assumed that there are only single collisions between the CB and OB and between the cue tip and CB. And is it assumed that the CB-OB collision occurs over only a fraction of the time taken by the tip-CB collision?
<blockquote><font class="small">Quote Bob_Jewett:</font><hr>I think the main clue is that the momentum of the two balls along the initial line of centers is equal. <hr /></blockquote>
What is the basis of that? The experimental evidence (HSV A.97 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-97.htm)) seems to be consistent with your statement, but you know me ... I like to know why.

Regards and thanks,
Dave

Bob_Jewett
07-29-2005, 03:33 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> ...
What are the assumptions made in such an analysis?<hr /></blockquote>
I'd assume that there is a relatively slow force acting on the middle of cue ball in the direction the stick is pointed.

The equal momentum along the line of centers is an observation, but I think it also follows directly from the above assumtion.

The fact that the natural times of the two two-object interactions are only a factor of five apart may cause some discrepancy.

I think what we need is a good FEA program.

Voodoo Daddy
07-29-2005, 04:54 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> <blockquote><font class="small">Quote Voodoo Daddy:</font><hr> Someone hand me a bucket <hr /></blockquote>
I hope you are just joking. If not, I take great offense at your subject and message.

I have worked my A** off this past week to shoot the videos, do the analysis, and post the results on this forum. If you think I did this because it would sell a few extra books, you have a twisted mind (IMHO). Do the math. The hourly rate is not that good.

Disappointed,
Dave /ccboard/images/graemlins/confused.gif <hr /></blockquote>

Sorry Dr Dave...I respect your occupation as a college professor but I wasnt joking. I may not be the smartest guy on the planet but I do know self promotion when I see it, guess it comes from 25+ years of playing the game I love and not disecting it. Ofensive or not, thats my opinion!!

Jal
07-29-2005, 06:52 PM
<blockquote><font class="small">Quote dr_dave:</font><hr>...
I kind of cheat it by pressing CTRL-P on the keyboard twice, quickly, to start and stop the clip. I found that this is much more reliable than clicking the mouse button on the player's pause button.

Does anybody know of any better solutions?

Dave <hr /></blockquote>

Thanks for the tip, I wasn't aware of this.

A frame by frame viewing of .avi files can be done with VirtualDub which I downloaded sometime ago (for free), but it won't read the .wmv files. Perhaps a newer version or something else can do the same for these. I'll check it out.

And thanks again for the mountain of work you generously share with us.

Jim

PastPrime
07-29-2005, 07:21 PM
You guys give me a laugh. Voodoo has his store listed on every message he posts which now seems to be several times a day where you never heard from him for months before and now he belittles someone who is interested in the details of Pool and trying to show this to any of the rest of us that may be interested. Go back and post your pictures of your "friends" store and stay out of Hal Houle's life who is another who is not looking for personal gain by the way and let Dr. Dave help the rest of us.

Voodoo Daddy
07-30-2005, 06:32 AM
<blockquote><font class="small">Quote PastPrime:</font><hr> You guys give me a laugh. Voodoo has his store listed on every message he posts which now seems to be several times a day where you never heard from him for months before and now he belittles someone who is interested in the details of Pool and trying to show this to any of the rest of us that may be interested. Go back and post your pictures of your "friends" store and stay out of Hal Houle's life who is another who is not looking for personal gain by the way and let Dr. Dave help the rest of us. <hr /></blockquote>

Past Prime...I have no problem taking my friends POOL ROOM's website off my tag if anyone believes that I'm "selling" anything...which is a joke in the first place. If Dr Dave and Hal Houle help you thats nice, but I have a different outlook. Do me a favor...enjoy your side of the fence and I'll enjoy mine.

dr_dave
07-30-2005, 09:07 AM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr> ...
What are the assumptions made in such an analysis?<hr /></blockquote>
I think what we need is a good FEA program.<hr /></blockquote>
I agree with you. Basic dynamics collision calculations don't tell enough of the story with multiple object collision. In addition to a finite element analysis (FEA), lots of experiments would need to be performed to accurate model all of the important material properties and physical effects.

Regards,
Dave

theinel
07-31-2005, 02:26 AM
<blockquote><font class="small">Quote Voodoo Daddy:</font><hr>Do me a favor...enjoy your side of the fence and I'll enjoy mine. <hr /></blockquote>
Voodoo, I don't in any way mean to offend you (I am stating that because text messages don't often convey meaning very well). Your last message stated your point well that you don't enjoy dissecting the game but it also said that Dave was self promoting himself which PastPrime took as an offense for whatever reason so attacked you regarding your sig which supports/promotes a pool room. From what I've seen Dave loves that game and contributes to it because he feels he has something to offer. I haven't met him in person, or Bob Jewett, but they both provide great technical insight into the game for those who like that side of things.

I love to play the game, I love to analyze it and I enjoy Dave's input. I also enjoy your contributions. Your quote above says it all. Why say something bad about Dave when you gain nothing from it? I don't know why I am making this post but I see too much opinion/commentary on these boards that I am sure would be understood or swept aside in a normal conversation but gets taken badly in text.

As an aside we might know each other or more likely know friends, or friends of friends. I'm from West Palm and Sunset Billiards came up last week when I was talking with Javier C. and Miguel R. at the TK event in West Palm. Next time I'm down your way maybe we can get together and play a few racks.

Voodoo Daddy
07-31-2005, 04:12 AM
<blockquote><font class="small">Quote theinel:</font><hr> As an aside we might know each other or more likely know friends, or friends of friends. I'm from West Palm and Sunset Billiards came up last week when I was talking with Javier C. and Miguel R. at the TK event in West Palm. Next time I'm down your way maybe we can get together and play a few racks. <hr /></blockquote>

Next time you talk to Javier if Big Steve helped them with their pool games. I worked with him and his brother Angel when I ran Flagler Billiards. As far as you and I gettin together...I'm down for it!!