kubotek

Elaborate on mathematical modeling of lures IMO

27 posts in this topic

Hello,

I have been reading TU for about 1 months now, I am extremely green on basically everything when it comes to making custom lures. I'm not sure what this topic will bring about, but i think most will find it interesting to some degree. I am a mold designer, that makes plastic ejection molds, along with compression, and composite molds. When I first seen your post I thought you were going to get into 3d CAD models of crank baits. I have attached a very simple model I drew. This you can find out center of gravitys mass related issues threw catia. Im not sure if anyone on here is fimialar with catia orr any other 3d cad software, but im sure at some point manufactures have to draw the lures in in some form. This file then can be sent to a cnc machine that tool paths can be created from. Also different locations for weights can be added drawn in locations, without having to actually drill any holes.

I have attached 3 pics of the files, cause IMO a thread isn't a thread without pics!

Any thoughts out there.

Kyle

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Kyle,

First things first... Welcome to TU, the center of tackle junkie universe. It looks like your going to fit in well with this crowd.:yay: Like the way you just jump in and run with an idea.

I believe your on the right track but, you also have to account for the fact that not everything is a pure science; art and nature also figures into it.

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Somehow I believe guessing that the handmade lures (ie...rapalas, storms) tested and tunned by hand must then be CMM (cordenant measuring machine.) and a report must be made of the surface location in a given space. From that you can bring the surfaces into CAD. I know i could take a lure made by one of you guys, and get it CMM'd then take that and get a aluminum mold made of that. This then could create an exact model of that handmade lure. Also you can make slight modification of that handmade lure and see the differences. I dono just a thought. What would be interesting the mold could be a multi cavity.

I dono maybe im looking to much into this.

Kyle

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Would definitely be neat, but even if it's the same weight and balanced the same, it's just not the same as a wood bait for some reason. Also, how much goes into molding the baits nce you get a mold? Is it reasonable for most of us?

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Thanks Clamboni. We should collaborate, I’ll send my technical posts over and you can translate them for TU!

Bruce. Nature is one big science lab. Art is fooling natures creation with my own.

Kyle. Welcome to TU. Wow, a fellow tube jockey! Just about everything that I model, goes over to you guys to generate the production tools. You are the guys that tell me, “you cannot do this, you cannot do that, the radius is too small, the pocket is too deep etc”. I would locate a smiley face here, to show that I am only joking, but smilies are not for me.

There are two subjects within the title ‘mathematical modeling’. One is CFD’s (computational fluid dynamics),which is a software that will take a computer design and apply flow to it and determine the result. CFD’s are still relatively in their infancy, but the day will come (very soon) when you will see your lure design idea swimming on your screen, long before you get your tools out. With CNC machines (computer numeric control), you might not even have to do that. Hell, you can even get a robotic arm to paint it. The second definition of mathematical modeling is what we do, basically, drawing in 3D.

Yes, we can manually carve and test prototypes. When we have something that works, we can collect the point data with some kind of digitizer and make a 3D model. This in turn is sent to DelW, who will send me an aluminium mould the very next day! These point digitizers are not even beyond the average designer. I have seen them advertised as optional extras on small CNC milling machines.

I’m not sure how the big boys operate. But I would imagine that at the very beginning of a project, some hand carving would take place. They may well go straight in with a computer model and rough a few out on the CNC. If I owned a CNC, I would not be doing any more hand carving. I would CNC a block of wood, make an RTV (rubber) splash and cast a foamy (expanded polyurethane foam) for testing.

From a CAD (computer aided design) designer point of view, working with point data on such a fiddly little subject would be a real pain, I would sooner model it from scratch, taking a few measurements and eyeball it. Catia V5 is a wonderful tool. The generative surface design is a dream come true. If you construct the models correctly, you can make a change to one of the first surfaces and everything drawn after that will be automatically changed. In other words, I can draw a basic lure shape, surface it up, add the lip, eyes, hooks, everything. I can then go back to the original sketch of the profile and alter the length, depth, thickness, radii of profile. The finished model will instantaneously re-draw to my new design. AWESOME!!!!

I hope you enjoy TU (tackle addicts anonymous) and come forward with some outlandish theories and innovative designs.

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Vodkaman... I got a question for you.. First im lost in Translation on the engineering side.... anyway.. THE ROBOT arm got me thinkin.. Im a video game junkie.. is it possible to hook my arm up to those video game suits that they use to copy player's movements like in Madden Football video game.. EA Sports trys to make it as real as possible and the some of the players dress up in some kind of computer suit and it put's there exact movements in the program.. Im curious to know if that possible for a robot to paint the exact way I paint .. kinda like copying someone's hand writing.. IF THIS IS STUPID QUESTION!!! Let the games begin..I can take it...

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I think I get what you mean. I'm not sure if this is still true today, but I know a few years ago, they used to train the robots in the car industry by manipulating the spray arm by hand. The control system would record or 'remember' the movements and replay at the appropriate efficient speed. Any errors or inefficiencies in the 'route' would be editted out, like editing a CNC path.

I'm sure the 'big boys' are using this type of technology or something similar, but I don't think you will find one on the shelves of the supermarket any time soon.

The computing tecnology to do this sort of thing is not that hi-tech these days. A computer program operating a bunch of servos, switches and actuators, could be stepper motors or hydraulics, just got to learn some.

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I think there is a slight over lapping of technologies going on... The pure programming of robotics mixed with the ergonomic replication of gaming software to provide a physical model of what is humanly possible for a simulated character. There are suits with sensers mounted externally about every set distance apart that can be displayed as a motion to that character model.

Say a certain scoccer player used a distinctive style to strike the ball. By having him/her wearing the suit and preforming this act, a computer motion model could be constructed.

I think the Rookie was wanting to model himself painting a given lure, a specific pattern, and have it then programed into a 4 axis robotic arm to produce "perfect copies" of said lure...

Oooch, it's time for an ice cold MEDICATION break. Happy to see there appear to be no long term effects from the actone.

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Bruce, that is pretty much how it works but without the glove.

Thanks for #& @^*# your concern, jus @$@%^ t a few twitches!!!!

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There are moments when, in a battle of witts, I feel totally unarmed... Does this make my butt look big???

I can almost see you sitting on the other side of the pond just shakin' your head and saying, "Crazy yank". I've seen it before by your country men. ;)

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Perceptive, but I do have a silly grin on my face.

Just guessing.... Maybe?

Well, alright then, talk about a derailed thread. I think this is a excellent example. Ha ha ha. It's only 4:42 am on my side of the world...

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I Believe that you are looking for a robot such as a moto man!

http://www.motoman.com/

We currently run these at my work. We water jet parts. Are model is a little different then this one. I know for a fact that are soft ware doesn't allow you to do what your asking. Im sure you can get some that will. But the cost would be out of this world. We payd 80,000 USD for the software that we have now. Its a very simple program also. The robots them selfs are cheap. The moto man HP50 we have cost $60,000 with the CNC controller.

Those could be used to paint. BUTTTTTtttt............................IMO youd want to have http://www.faro.com/content.aspx?ct=di&content=pro&item=2

With this, you could track your airbrush moves. Now it be not practical to have this do to cost. But if you had udles of money that you wanted to throw around you could do that. These are designed to get points in space. The robot arms always knows where it is. so as you move it to a point it then nows where that point is. You have to still get them or you to re write the code to allow the software to record the amount of air pressure to paint your allowing threw. If you were a small company, im positive you could get R&D money that would fund all of this. I know this because my work is huge into R&D, But the cost of this would be clearly not possible for a small lure builder.:angry:

Its to bad a (THE BIG GUYS) Like rapala isnt on the site.

Kyle:whistle:

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Not a painter myself, but I have just been waiting for their input. I suspect that the most enjoyable part of lure making (apart from cashing the occasional cheque) is applying the paint and seeing the block of wood come to life.

Clemmy, the clown is my uncle Trev and his wife Anne. The dude in the middle is Emlyn Hughes, ex Liverpool soccer player. Trev is one of my heroes. He quit a high paying exec job to become a professional party clown and makes a descent living at it too.

I wanted to demonstrate what a grin was, he never stops grinning. A real happy guy.

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Well the more I think about it.. I guess I would rather program it to rub my wife's back than paint a lure!!! Think of all the time we could saved Men across the world...

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I'm not sure what this topic will bring about, but i think most will find it interesting to some degree.

Kyle

ok,ok.... i originaly posed this question to the forum. it brought alot of mixed feelings. tons of debate. i think allot of old school builders were somewhat against this concept. with a simple model it might be possible to design all the theoretical ideal balances of bill shape to body. my interest was not to perfectly model all the aspects of fluid dynamics, or taking acount of surface drag differences(between different paints or textures). instead i think that if as many of these varriables are removed and distilled into a simple function then we could explore/understand that say for every body length and body height we have set ideal lips that will produce the absolute theoretical maximum/and or ideal wobble. many people previously believed that there are too many varriables that affect lure motion. while many things may affect it, i still believe that a distilied grand unification(simplification) theory is possible in the universe of lure building. this holy grail of formulas would greatly help and accelerate many peoples understanding of lure design.

finaly. i would mention that i have recently come apon the realization that each lure probably has an optimal speed that it will occelate maximaly at. that said, i think that i can roughly mentaly see, that as the lure gets bigger and bigger the running speed must get progressively faster to produce the affect of wobbling.

now at least if nothing else a simple formula could be written that could be used to estimate lure size based on the speed that the target species typicaly chases it prey.

but again, my original interest was to graphicaly show all the optimal lip shape and size in relation to the length of the lures. we are just on the verge of this simple function being openly understod.

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Goldenshiner. That was one of the great threads, at least in my lowly opinion, but I would say that, I am left brained!

I am in total agreement with you on all your points above. If people are not interested in the technical discussion, they should step aside and let those that are get on with it, everyone has a choice. I firmly believe that if you have nothing positive to say then say nothing.

Yes, there are a lot of variables to take into consideration. But, as we are not trying to nail the solution to the milligram, I believe many of them can be side stepped and we should concentrte on the biggies, namely: lip geometry, eye location, ballast location and body shape.

It is a daunting task to deal with even just these four at once, but it is possible to nail three and vary the fourth, in fact this is the standard procedure for prototype testing. You only change one thing at a time, otherwise you don't know which adjustment worked and you have to go back twice more to find out. Patience is the name of the game.

When I joined TU, it was my intention to create a spreadsheet to do exactly as you stated. Enter your lures parameters and it will tell you the result. I tried for a while and will probably return to it some time in the future, but I am more of the opinion that it is sufficient to just understand how everything works, to design a new lure from scratch.

Yes, the calculations are complex and require a fast computer, days to run a simulation. But I believe that an approximation is possible, like we said, we are only looking for a rough guide.

But, before I could calculate anything, I had to find out exactly how everything works. This too has been a real trial. I feel that I am close to understanding the major principals, but not absolutely confident. Unfortunately, the learning curve has now kicked in. All the testing that I have done has given me an instinct for a lure, I can usually tell how it is going to behave in the water.

But the whole point of this exercise was to help the newcommer to the addiction and try to minimise the learning curve. This is the part that dissjointed a few noses, "why should anyone get my hard earned knowledge on a plate"? Well, if anyone has that selfish opinion, then tough, because that is my intention, to put it on a plate, for new members and hopefully enough to enhance the knowledge of a few of the more experienced builders. As I work out little parts of the puzzle, I will continue to post them for debate. This process is a good way to test the theories, as all the theories should work together for every case, for all baits, hard, soft, lipped, lipless etc.

Well enough soapbox. As for your reference to the size and speed. Very simple calculations are available for this one. Do a web search on Strouhal number. Top of the page will be wikapedia. This pretty much covers it in a nutshell. While you are there, look up vortex shedding and Karman vortex street. This covers all the lip theory. Having read these subjects, designing new lures is just a matter of interpretation and application of these principles.

Anyone else have any ideas or theories? Publish or be damned I say, bring it on!

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My theory is that I can understand what you guys say when I read it, but it vaporizes from my mind the minute I turn the computer off! Probably due to some vortex in the back of my head. :o)

But it's fun reading what you write.

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Vman.

In my messed up right brained head, I really do find that I consider lure making to be more "art" than "science" and tend to use a "gut" feeling when I set out to catch a particular species of fish or consider if a given lure will catch them. When I was growing up my attempts at lure crafting centered around tying flies and streamers, trying to match nature and the “natural flow” of the hatch in the water.

As a kid, I used to lie on the dock with my little brother, staring into the water below. We’d play with fish, a few feet of fishing line, a hook, and some bait. We would do this for hours… Seeing how a yellow perch would suspend under the dock in the shadows, watching the minnows just inches away. The predator and the prey would maneuver just enough to maintain position, trying not be seen the one another. As this game of life builds, there is a quick, sudden flash of movement and a fraction of a second later, only the perch remains. We would also experiment with different baits, things like corn, hot dogs, worms, bugs, anything we could our sticky little fingers on would likely end up on that hook. We would watch and repeat this process over and over to study the effects in detail.

In my heart, the idea of developing a model formula for specific lure types makes perfect sense. I can see how a formula to compute depth, wiggle, distance, etc., can establish “fixed” variables to a standard equation. However, when I apply my goofy, right brain tendencies, that I’ll refer to as the “spike-a-pike” factor (or “SAP” factor for short), the fixed variables quickly fall out of equation.

Will I twitch the “perfect lure” 2 inches or 2 feet? Do I leave it settle in the water until it’s perfectly still or do begin to retrieve with a sharp pull on my pole, getting the lure to a depth of 2 feet; suspend the lure completely still for a second, rip it a few feet, stop, suspend, rip, repeat… This “SAP” factor is my feeble attempt of applying the elements I watched dock side 40 plus years ago into each lure I touch.

As a mechanic, I could bolt a jet engine onto a test stand. If it was a “new” engine, fresh from build up, the first step was to assess the current condition of that engine. Was anything loose or missing? It had to meet a set specification before we would ever attempt to spin the compressor. As we applied air to the turbine wheel, we would perform a detailed set of leak checks for JP-4, oil, and hydraulic fluid. Did the nozzle travel of the afterburner comply with the established measurements for “0” percent and “100” percent nozzle dimensions? Every aspect of a test cell run was to make absolutely positive that each engine was a perfect copy of the engineering spec and we’d bet the pilots lives that on that fact.

I just can’t apply an absolute engineering specification to a fishing lure when there are so many factors that aren’t absolute. We can make them all exact duplicates to zero deviation tolerance in size and weight, but, there is no absolute manner to ensure it will always be employed by other goofy right brained fools like me. The SAP factor happens.

Just more fodder to factor on that der slide rule ya’ all.

Merry Christams and thanks for making me think... Cheers

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Bruce, a good response, I can live with that opinion, even agree. What I have a problem with is being told, "can't, it's too hard". Any solution is going to be an approximation or even statistically based. maybe using real feedback from testing prototypes and interpolating between cases. It will be a while before I consider tackling that one again, but I will, one day.

I too studied the fishies from a dock. My problem was I very rarely caught anything. One day I asked a guy fishing next to me, with a net full, what was I doing wrong. He took a time out and came over to my swim, took one look at my gear and told me the line was too thick, the fish can see it. There was a pier there. So I dropped a handful of maggots in. They never reached the bottom. I then lowered my loaded hook with another handful. Same happened again, except my hook maggot was not touched. Life changing experience. From that day on I slayed them, using 2lb line max. Some days, when the fish were difficult, I would go down to 3/4lb line with No24 spade hook.

So, when I joined TU and found that you used 10lb line I was horrified! But, fishing lures is a very different game to bait fishing. I now enjoy both. Glad I got to exercise your mind.

Happy holidays to you all.

Dave

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