Primitive Archer

Main Discussion Area => Bows => Topic started by: lleroy on February 19, 2019, 12:01:23 pm

Title: bow-simulator
Post by: lleroy on February 19, 2019, 12:01:23 pm
Anyone given this a spin yet?
http://bow-simulator.org/

Title: Re: bow-simulator
Post by: Pat B on February 19, 2019, 02:22:57 pm
I'd rather shoot bows and arrows than read about shooting them. I guess someone will be more enthusiastic than me about this.
Title: Re: bow-simulator
Post by: bradsmith2010 on February 19, 2019, 02:30:17 pm
its probably a great tool,,
I am old, and just like to make them,,I think I am a bit lazy too,,
so I just scrape with a wrasp and hope for the best,,, :NN
Title: Re: bow-simulator
Post by: Stick Bender on February 19, 2019, 03:41:50 pm
It's probably a good program but how usefull it is I don't know, I know guys that have used limb thickness & taper calculators & in the end most of them got it wrong , I don't think there is any substitute for good old fashion making the bows & perfecting the design most designs you can get a good concept of where to start with out soft ware , maybe I'm old fashion to ,I like doing all the R&D myself ! There are so many variables in making bows I don't think any soft ware could calculate it right on the first go , what's next where going to use computers to talk about primitive bows  ::)
Title: Re: bow-simulator
Post by: willie on February 19, 2019, 04:20:25 pm
I couldn't get it to load, but that has been a while back before some bugs were fixed. I use david deweys spreadsheet to rough out designs then  finish by eye
Title: Re: bow-simulator
Post by: Selfbowman on February 19, 2019, 11:48:26 pm
Not smart enough to work it but I have been thinking about the use with glass bows. I think in the end building different designs with different types of materials will win out.. this is in the glass world. In the all wood world I have been moving mass around in the limbs for some years. Sometimes you just have to get lucky. To many variables with wood. But thinking out side the box got us the first bow thousands of years ago. Just saying.   Arvin
Title: Re: bow-simulator
Post by: Ryan Jacob on February 20, 2019, 02:46:35 am
I mean, if you already know what’s gonna happen, doesn’t that take the fun out of it?
Title: Re: bow-simulator
Post by: Swampman on February 20, 2019, 06:30:51 am
I work on a computer all day for my job.  The last thing I want to do is bring a computer into the mix of my shop time.  I think what I like so much about this hobby is taking an imperfect piece of wood and figuring out how to get a bow out of it. I like to use just the software between my ears for this.  It does fail me sometimes but that is part of the fun.
Title: Re: bow-simulator
Post by: Jim Davis on February 20, 2019, 08:06:56 am
I'd find it interesting if I could find a switch to take it out of metric mode...
Title: Re: bow-simulator
Post by: avcase on February 20, 2019, 10:39:52 am
I mean, if you already know what’s gonna happen, doesn’t that take the fun out of it?

I guess it depends on the person. For me, it allows me to focus on the bow design aspects that I know will help me achieve my goal. I wrote a similar program and it yielded some pretty useful discoveries about how bows work and how to make them work better. I see it as being no different than an interactive version of a book on bow design. ;)

Alan
Title: Re: bow-simulator
Post by: bradsmith2010 on February 20, 2019, 12:06:31 pm
I rather ask you guys,, see I think I am lazy,, :NN
Title: Re: bow-simulator
Post by: Bayou Ben on February 20, 2019, 01:59:04 pm
I tried this out when you 1st put it out, maybe a year ago?  I can't remember what the issue was, but I couldn't simulate what I was trying to build, so I didn't go any further.  If I get some time, I'll download it again and see if I can identify the problems I was having.   

It's not for everybody, and not for every bow, but I have always wanted something like this when going for performance.  It would be great to know that bow A with deflex here and reflex there, will theoretically store more energy than bow B with r/d in different positions.  No, this doesn't build the bow for you but it could save you from building 10 prototype bows to find the one that stores the most energy. 
 
Title: Re: bow-simulator
Post by: DC on February 20, 2019, 02:27:38 pm
Can't get it to start. It starts to open then I get a window with 3 error messages and it closes before I can read them.
Title: Re: bow-simulator
Post by: bradsmith2010 on February 20, 2019, 03:25:13 pm
I read some guy was winning flight shoots using something like that, but for arrows,, (--)
Title: Re: bow-simulator
Post by: willie on February 20, 2019, 05:21:52 pm
I read some guy was winning flight shoots using something like that, but for arrows,, (--)


interesting.......... any links to help track that down?
Title: Re: bow-simulator
Post by: avcase on February 21, 2019, 01:09:10 pm
I read some guy was winning flight shoots using something like that, but for arrows,, (--)

I use these kinds of tools for designing flight bows and arrows, but I don’t recall winning much!  Hahaha!

I rarely find time to make more than a few bows per year, and I almost never make the same design twice so I need to try my best to get it as close to right the first time. This is where these tools have helped. 

Alan
Title: Re: bow-simulator
Post by: willie on February 21, 2019, 04:02:30 pm
Alan, did you notice the screen shot for the app that shows string energy fluctuations?

Code: [Select]
http://bow-simulator.org/images/screenshot_05.png

(the graph looks nice, I would like to peek at the underlying maths)
Title: Re: bow-simulator
Post by: bradsmith2010 on February 21, 2019, 04:29:55 pm
I think I read it on the flight bow section...if I remember better I will message u
Title: Re: bow-simulator
Post by: avcase on February 21, 2019, 06:03:15 pm
I think I read it on the flight bow section...if I remember better I will message u

I hadn’t noticed this plot but that is an incredible way to show what happens to the energy stored in the bow, from the time the string is released, through the time the arrow leaves the string.  When I was finally able to visualize and understand this energy dance, it completely changed the way I look at how a bow works.

This single graph gives an enormous amount of information about this particular bow design, how it works, and how to make it work better.  It would be next to impossible to get this feedback on a bow design any other way. I give this a big thumbs up!

Alan
Title: Re: bow-simulator
Post by: DC on February 21, 2019, 06:47:28 pm
So I take it you guys got this software to run?
Title: Re: bow-simulator
Post by: ccase39 on February 21, 2019, 06:54:58 pm
I mean, if you already know what’s gonna happen, doesn’t that take the fun out of it?

I guess it depends on the person. For me, it allows me to focus on the bow design aspects that I know will help me achieve my goal. I wrote a similar program and it yielded some pretty useful discoveries about how bows work and how to make them work better. I see it as being no different than an interactive version of a book on bow design. ;)

Alan
This. It’s a different world now. These days people can watch enough YouTube or go to message boards along with practice and gain as much knowledge as people who have been doing it all their lives. 20 years ago if you wanted to learn a craft you had to find someone to teach you. Especially if it is something like bow building that isn’t practiced everywhere. You still need good ole hands on trial and error but you don’t have to wait 2 weeks until you and your buddy can carve out time away from work and family in order to share knowledge.
Give me a YouTube video and a couple of deer to practice on and I can do a triple bypass in a month.
Title: Re: bow-simulator
Post by: willie on February 23, 2019, 07:06:00 pm
Quote
This. It’s a different world now.

CC, I think you are right, there are young guys here that have never known a time there was not a computer around. as ubiquitous as jackknife was to a lot of the older guys on here, I guess it could be just another tool in the box for most.

so I brought the simulator up in the appimage version, but am not sure it has full functionality.

does anybody have it working? right now I am still Reading TFM.
Title: Re: bow-simulator
Post by: lleroy on February 24, 2019, 02:03:48 pm
so I brought the simulator up in the appimage version, but am not sure it has full functionality.

does anybody have it working? right now I am still Reading TFM.

I have it working on Windows and on Linux
(I even have compiled the in-development version :-) since It's open-source )

I attached a few attempts to simulate self-bow designs I'm interested in...

btw: those buttons on the right-bottom 3D view don't do anything (yet)
(but I noticed that's fixed in the in-development version)

just go for the green arrow on the toolbar
Title: Re: bow-simulator
Post by: Pappy on February 25, 2019, 05:08:10 am
Yep, different world for sure. ;) :) :)
 Pappy
Title: Re: bow-simulator
Post by: willie on February 25, 2019, 05:04:28 pm
I had a chance to play around with the bow simulator this past weekend and I think it is quite useful.

you can "draw" out your bow in length, width and thickness in a quick sketch or in minute detail. input deflex, reflex and recurve. there is even a feature to design a composite or laminate of differing materials. one part many might find useful is the static simulation feature. By moving a slider the designer can see what his bow should look like at any point along the draw curve.

Recently there was a thread discussing how one should be able to see the limb bendshape develop as the bow is tillered out longer. I think it was a deflex/working reflex that the bowyer thought should have the limbs go straight at some point in the draw. this application could help visualize

one can design and evaluate before building or input an already glued up laminate or pre-bent stave to see how it should bend.

a dynamic simulation feature seems exciting, as it indicates in a graphical chart where the energy is stored and released when the bow is shot. limbs, arrow and string are all part of the outputs.

Hopefully, the project will find a home in more than a few toolboxes.

lleroy, I will have to look over those .bow files.  it seems that my old distrubution had trouble with the appimage, but an update got it working well.
Title: Re: bow-simulator
Post by: DC on February 25, 2019, 06:31:06 pm
I have tried a bunch of times to load this. I even got my grandaughter to try it on her computer. It works for her. She's very good with computers and she couldn't figure out why it won't work on mine. I get these error mesg. Anyone got a clue what's happening
Title: Re: bow-simulator
Post by: willie on February 25, 2019, 06:47:37 pm
not really a windows guy, but are you trying to run a 64 bit application on a 32 bit machine?

Title: Re: bow-simulator
Post by: Bayou Ben on February 26, 2019, 07:38:43 am
I was thinking the same thing Willie.  Did you try the other download link DC?

This program is pretty awesome.  The user-manual is easy to understand.  Thanks for putting this together lleroy. 

I have one request and I hope it can be done without much trouble.....English units??  Sorry I haven't worked in metric in over 10 years and it's taking me a while to convert each value. 
Title: Re: bow-simulator
Post by: DC on February 26, 2019, 08:10:00 am
Yes I tried both. Got the same results. I'm just hoping lleroy has run across this before.
Title: Re: bow-simulator
Post by: lleroy on February 26, 2019, 12:53:59 pm
Thanks for putting this together lleroy. 

I have one request and I hope it can be done without much trouble.....English units??  Sorry I haven't worked in metric in over 10 years and it's taking me a while to convert each value.

I'm not the author of this program... I just posted the link.  :)

Title: Re: bow-simulator
Post by: lleroy on February 26, 2019, 12:57:09 pm
she couldn't figure out why it won't work on mine. I get these error mesg. Anyone got a clue what's happening
what computer are you using Win10? (or older: win7? Vista?)
looks like the program has a problem initializing your graphics card's 3D support...

Title: Re: bow-simulator
Post by: DC on February 26, 2019, 01:09:28 pm
It was Win 7 Home Premium when I bought it who knows how long ago. It's Win 10 now. It was a bare bones computer so the graphics card may not be much. I wouldn't want to spend money on a card and then have the computer die(again, I've replaced the hard drive) decision time I guess. Thanks
Title: Re: bow-simulator
Post by: stfnp on February 26, 2019, 01:45:42 pm
Hello everyone,

I'm the author of that program, willie has pointed me to this thread. I'm glad some of you like it and find it useful. Keep in mind that it's not yet finished by far. It's more of a starting point. That's also why I'm always interested in suggestions and feedback.

I get these error mesg. Anyone got a clue what's happening

Yes, that's a problem with the 3D graphics, as lleroy said. Sorry for the inconvenience. The next version of the program should be more compatible with older hardware. I hope to get it ready in the next few months...

Stefan
Title: Re: bow-simulator
Post by: DC on February 26, 2019, 03:19:10 pm
Thanks. I just went looking at 3d graphics cards and they range from $9 to $900. Yikes!!! I hate to spend a bunch of money on an old computer. Can anyone recommend a cheap card that will run this program?
Title: Re: bow-simulator
Post by: willie on February 26, 2019, 05:05:18 pm
Stefan,

the energy graphing is a real eye opener, especially being able to see the relative proportion of bow/string/arrow energy. Did you utilize the marlow formulas to work up your algorithms? I am guessing that you have tried to verify some arrow velocity predictions with a chrono?

quite a project you have in the works :)
Title: Re: bow-simulator
Post by: stfnp on February 27, 2019, 02:49:00 am
Thanks. I just went looking at 3d graphics cards and they range from $9 to $900. Yikes!!! I hate to spend a bunch of money on an old computer. Can anyone recommend a cheap card that will run this program?

What graphics card do you currently have? You could try installing the latest drivers from the manufacturer's website, if available.

the energy graphing is a real eye opener, especially being able to see the relative proportion of bow/string/arrow energy. Did you utilize the marlow formulas to work up your algorithms? I am guessing that you have tried to verify some arrow velocity predictions with a chrono?

I have read that paper from Marlow and applied some of the results to my own model. But it's a different approach. My program uses finite elements, so the limb and string are approximated by a large number of little "segments" or "elements" connected to each other. There is an unfinished technical documentation here (http://bow-simulator.org/resources/) if you want the excruciating details. Unfortunately I don't have a chrono yet. Might be a good investment though... For now I have only verified some of the static results with simplified test bows.
Title: Re: bow-simulator
Post by: willie on February 27, 2019, 05:41:10 pm
I have it working on Windows and on Linux
(I even have compiled the in-development version :-) since It's open-source )

lleroy,
I tried to look at your .bow files in the appimage version, but they would not load. What version did you use to create them?
Title: Re: bow-simulator
Post by: willie on February 27, 2019, 06:07:45 pm
a little research about FEA has been on the reading list for a while,  so this might be a good time to start, thanks.


Title: Re: bow-simulator
Post by: lleroy on March 04, 2019, 12:58:29 am
I've made them using the self-compiled version, that's somewhere between 0.5 and 0.6.
(if there is interest, I will remake them so that they open in the latest-released version, ie: 0.5,
but that may not be before next week)

I have it working on Windows and on Linux
(I even have compiled the in-development version :-) since It's open-source )

lleroy,
I tried to look at your .bow files in the appimage version, but they would not load. What version did you use to create them?
Title: Re: bow-simulator
Post by: willie on March 04, 2019, 05:02:24 pm
lleroy,
that might explain, if the .6 is unreleased. no need to redo unless you just want to share, as I was just curious.
Title: Re: bow-simulator
Post by: willie on July 01, 2021, 07:48:21 pm
this project has become Virtual Bow.

Is anyone using this program? Thoughts and comments if you are.

I can't figure out what the expected input for the width is.

I learned to use it more this past winter, although I have not built a bow with it yet. The program is actually very useful for laminated bows.

widths are stated in meters at some percentage out the limbs length. the table does not have to be in order
Title: Re: bow-simulator
Post by: Don W on July 01, 2021, 08:50:31 pm
I'll try and work through it. I have a few hickory stave drying I can try it on. I have a few other to finish first, but maybe I can figure the program out in the mean time.
Title: Re: bow-simulator
Post by: willie on July 01, 2021, 09:05:00 pm
It will be interesting to see what you come up with.  If your hickory is from the same source, you can model an existing bow to solve for the required MOE (stiffness), then easily tweak the model into an improved design. The data entry method in virtualbow was developed for ease of reverse engineering.
Title: Re: bow-simulator
Post by: SLIMBOB on July 01, 2021, 11:20:00 pm
I don’t make glass bows, but I know a guy who does. Programs like this are what he uses to experiment with different design tweaks. For an all wood bow, to many variables to be accurate I think, but maybe a useful tool for an experienced guy to, once again, tweak the designs here and there. If used as a shortcut to simply bypass the design and tillering stages, you kinda missed the fun part. My 16 year old son would disagree with most of the above.
Title: Re: bow-simulator
Post by: lleroy on July 02, 2021, 05:42:03 am
I used this program to make a some virtual bows, to see how a specific design works, and understand how it's spreading the stress along the limb. So for me it's an interactive version of the TBB where you can produce F/D curves and experiment with profiles.

It's much easier to make a virtual bow an inch longer or 1/8 inch wider than a physical bow :-;

I haven't used it as a "design" tool, but it's a valuable learning tool.
(as mentioned above, too many variables in real wood compared to laminations)