Soliciting advice for unusual build

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    Default Soliciting advice for unusual build

    I'm researching building a CNC machine that has a working surface area of 2 feet by 4 feet. The purpose of the machine is to move to and push up an array of rectangular shafts in order to represent a 3 dimensional terrain. Others have made similar dynamic shape display systems, however my application need not be so dynamic, nor expensive. The goal is to be able to push up the pieces, one at a time to represent a rough interpretation of a terrain map (i.e not dynamically move based on motion sensors). What I hope to build is an array of the rectangular shafts that will be "pushed up", one at a time by a X/Y CNC machine from below. The goal is to be able to manipulate 10,368 shafts in just a few minutes.

    To be honest, I need engineering help/advice to solve 3 major issues.
    1) A way to rapidly push up each shaft to a variable position. I'm working on a solution in which a solenoid would energize in succession, essentially "pumping" each shaft to crank it up a notch each pump until the desired height is met. I'm working on a 3d printable model of a shaft that has a bottom plate that when upward force is applied it will "ratchet" the shaft up a notch; so energizing a solenoid under it 3 times would ratchet it up the 3 positions below baseline I need. That said, there's probably a better way and am open to any suggestions.
    2) Speed. The 3d rendering of a terrain map should happen within a few minutes. I think this is achievable without having to have 1:1 solenoid to shaft as in the MIT's inForm machine, but I have no experience in making CNC machines fast... looking for any advice.
    3) Cost. This is a hobby project. I don't anticipate this being a marketable product (at least in my application), and am doing it as a hobby. Cheap is king here.

    Now, for the "why" of this machine. A couple years ago I built a table with an integrated smart TV to play table top games like Dungeons and Dragons. Since then I've often thought, how cool would it be to be able to represent a 3D dungeon (walls, passage ways, etc...) via robotic means. What I'm hoping to do is build another table with this machine built in (along with software to manage dungeon maps; did I mention I'm a software engineer?). So, like I said, its a hobby that will likely only ever go as far as my players, but think how cool it could be to spin up a 3D game board at will...

    Any/all advice welcomed.

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    Default Re: Soliciting advice for unusual build

    Speed vs cost.
    Unfortunately, speed costs money, so the faster you want to go, the more it will typically cost.

    Define what you mean by "a few minutes". Is that 5, 10, 15 minutes.
    At 1 block per second, which would be crazy fast, it would take nearly 3 hours.
    To get to 1 hour would be 3 blocks/second. Crazy, crazy fast.

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    Default Re: Soliciting advice for unusual build

    Thanks for the reply and for the sanity check. I was hoping for 5-10 minutes, but that may be a pipe dream.

    I'm guessing the slow part will traveling to a positioning + pushing 10k individual shafts. Perhaps the mechanism to "push" up each piece can be designed to "draw" while in motion. For instance, the head can travel X/Y to the starting point, then Z axis can raise and then continue on an X/Y path to continuously push up as it moves (like a CNC mill, without the drill bit). Then make multiple passes to push up those that are 3rd/4th elevation settings. Less stopping and raising/lowering the head (or energizing solenoid) should be quicker? I'd need to come up with a shaft design that would be compatible with this, but I think that can be done.

    Also in practice, I would estimate less than half of the shafts will have to be raised for a given map, though that still leaves a lot of work for the machine to do.



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    Default Re: Soliciting advice for unusual build

    Something like this, to be reasonably time-efficient, would want to push all the shafts up simultaneously, or close to that. If each shaft was on its own hydraulic piston, all you'd have to do would be to pump in the amount of fluid corresponding to a given height. But it's hard to do this cheaply; all those pistons would add up, not to mention the valve array needed to supply them. Memory wire would be easier to control; all it would take is delivering the right amount of heat to each memory-wire spring positioned under each shaft, which you could probably do with an array of resistors.

    But if you don't need it to be quick, then sure, having a single pusher rod underneath an array of pins held with the right amount of friction would be the cheapest and simplest way to go. Just set up a rastering path for the pusher rod, set up like the Z axis in a CNC machine but upside-down. There's no problem in assigning a separate Z height to each of 10,368 shafts; just allow a few seconds for it to get into position, push to a certain height, withdraw, and traverse to the next position. If each shaft takes 5 seconds, which seems pretty reasonable, that's just over 14 hours to set up each game. But those games take a long time to play, and you don't need to re-set it up immediately, do you?

    [FONT=Verdana]Andrew Werby[/FONT]
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    Default Re: Soliciting advice for unusual build

    Just to make the math easy, let's assume a 100x100 matrix of shafts.

    Then let the X axis have 100 positions, and the Y axis consists of 100 tiny steppers, each driving a tiny lead screw. Each stepper would be connected to a driver that is computer controlled. Something like these. https://www.amazon.com/Acxico-2-phas...strial&sr=1-12

    This would allow an entire row of shafts to be positioned at the same time at each stop on the X axis. Not near as fast as the inForm machine, but a bit less complicated. To reset, you would manually push the shafts back down to the base position.

    Would require a bit of engineering to get this to work, but it should do the job in a reasonable time. Shouldn't take more than a few minutes to set all the shafts.

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Soliciting advice for unusual build

    "Addressable pixels" come to mind. Replace the LED with a solenoid or a tiny motor... Although 10 000 of those would not be cheap or easy to assemble.





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    Default Re: Soliciting advice for unusual build

    For ambience alone I would rather look into fast 3D printing with recyclable/biodegradable materials.
    https://www.google.com/search?q=3d+print+d%26d+terrain

    Looking at your specs (2x4 ft^2) and 10,368 rods I arrive at 71mm^2 per rod or roughly ~8 mm 'diameter'.
    That translates to a pretty big nozzle size for a 3D printer.
    Materials galore:
    https://www.aniwaa.com/guide/3d-prin...le_3D_filament

    Your 'job' would be to find a suitable process, i.e. material/printer config with future improvements being to economically color it while its being printed (something your rod approach will never be able to do) and the whole thing being done within a reasonable time frame.
    The low resolution of your CNC approach will help with the latter, esp as the 3d printer comes out relatively large (if you want the result in one piece).



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    Default Re: Soliciting advice for unusual build

    Quote Originally Posted by awerby View Post
    Something like this, to be reasonably time-efficient, would want to push all the shafts up simultaneously, or close to that. If each shaft was on its own hydraulic piston, all you'd have to do would be to pump in the amount of fluid corresponding to a given height. But it's hard to do this cheaply; all those pistons would add up, not to mention the valve array needed to supply them. Memory wire would be easier to control; all it would take is delivering the right amount of heat to each memory-wire spring positioned under each shaft, which you could probably do with an array of resistors.
    Oooh, memory-wire... googling that now.
    Quote Originally Posted by awerby View Post
    But if you don't need it to be quick, then sure, having a single pusher rod underneath an array of pins held with the right amount of friction would be the cheapest and simplest way to go. Just set up a rastering path for the pusher rod, set up like the Z axis in a CNC machine but upside-down. There's no problem in assigning a separate Z height to each of 10,368 shafts; just allow a few seconds for it to get into position, push to a certain height, withdraw, and traverse to the next position. If each shaft takes 5 seconds, which seems pretty reasonable, that's just over 14 hours to set up each game. But those games take a long time to play, and you don't need to re-set it up immediately, do you?
    LOL, these games do take a long time, but we may sequence through 3-6 maps in a session (~3-4 hour sessions).

    Thanks for the ideas. Much to consider.



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    Default Re: Soliciting advice for unusual build

    Quote Originally Posted by Jim Dawson View Post
    Just to make the math easy, let's assume a 100x100 matrix of shafts.

    Then let the X axis have 100 positions, and the Y axis consists of 100 tiny steppers, each driving a tiny lead screw. Each stepper would be connected to a driver that is computer controlled. Something like these. https://www.amazon.com/Acxico-2-phas...strial&sr=1-12

    This would allow an entire row of shafts to be positioned at the same time at each stop on the X axis. Not near as fast as the inForm machine, but a bit less complicated. To reset, you would manually push the shafts back down to the base position.

    Would require a bit of engineering to get this to work, but it should do the job in a reasonable time. Shouldn't take more than a few minutes to set all the shafts.
    Very interesting approach! I could definitely see that solving the speed issue. I wonder the limits of independently controlling 100 steppers at a time are?

    - - - Updated - - -

    Quote Originally Posted by CitizenOfDreams View Post
    "Addressable pixels" come to mind. Replace the LED with a solenoid or a tiny motor... Although 10 000 of those would not be cheap or easy to assemble.
    Another very interesting approach, and one I didn't know was a thing Off to googling.



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    Default Re: Soliciting advice for unusual build

    @JoanTheSpark, This I agree with; printing would give a better overall look. I print small 3D terrain pieces now which we use to augment the digital maps when needed. I will definitely need to dig further into this idea if there's a way to quickly print and recycle. I suppose I could print a few maps before a session to anticipate what my players would encounter, however if you've ever played D&D (or DM'd one) you'll know that the game rarely follows pre-planned paths. I'm looking to add a quick'sh impromptu map that would be specific to random encounters.

    Thanks for yet another approach to solve this problem!



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    Default Re: Soliciting advice for unusual build

    If there isn't too much variation required, 3D printing (or even CNC carving) would be a good way to go. It would be simpler to make 100 terrains than to set up this machine to vary them infinitely. Once you had them mastered, you could use a vacuum-former to produce multiples off the master models - you could even sell them, since they're quick, cheap and easy to make.

    [FONT=Verdana]Andrew Werby[/FONT]
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    Default Re: Soliciting advice for unusual build

    Interesting problem. I'm thinking you need to 3d print but not using plastic but deposit magnetic particles one at a time. So have two print heads full of tiny magnets one noth pole, the other south pole, and deposit a north pole on a south pole and vice versa so they hold themselves in place, but can just be collected back into the print heads when done.
    Or maybe a single print head and magnetize them before placing them.



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    Default Re: Soliciting advice for unusual build

    Hi A - There are 3D changeable moulds that work this way but they use a membrane over the "pistons" The pistons push up and create the surface shape needed. This may decrease the amount of steppers needed to create the surface say by a factor of 10x?? Yacht sails are "Moulded" like this. But can't do a wall like this. maybe its good for terrain then print walls etc on top of that....

    https://www.northsails.com/sailing/e...ing-minden-usa

    https://patents.google.com/patent/US6354561B1/en

    cheers Peter



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    Default Re: Soliciting advice for unusual build

    awerby, Good point, and there are many companies that sell modular dungeon tiles and even many 3d STLs that I could tweak to make something print. The goal for me is to make it computer controlled and dynamic. Our games are very much player led, so as players make choices they can encounter an infinite number of scenarios that would call for a custom map. Currently we'd either roll out a dry erase map and draw the map with makers, or pick from a library of digital map that kinda fits the situation to display on our embedded TV. These are both fine solutions, but wanted to geek it up a notch. I'd like for the game master to be able to draw some lines on a screen and have those lines pop up as walls or rocks, or trees, higher elevations, pits, etc...

    BeNimble, that's a very interesting take! I can see how that would add a lot of flexibility, though I wonder at the speed. I'm hoping to find a way to "draw" a rough map out in 5-10 minutes tops.

    peteeng, hmm, cool idea. So this membrane would hold its shape after the pistons pushed it up? I wonder what material would work well for that in a reusable and repeatable fashion?

    So many good suggestions here! I'm spending more time googling ideas I never even knew existed. Thank you all for your thoughts!



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    Default Re: Soliciting advice for unusual build

    Hi Aadams - The 3D mould is usually 2 or 3 membranes thick. Sometime s there are battens between the pistons. What you really want is a holographic system. cheers Peter



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    Default Re: Soliciting advice for unusual build

    Or just get everyone to wear AR glasses. As well as having terrains that could appear and disappear instantly, you could have the dragons roar and rampage.

    [FONT=Verdana]Andrew Werby[/FONT]
    [URL="http://www.computersculpture.com/"]Website[/URL]


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    Default Re: Soliciting advice for unusual build

    A magical city where everyone must wear glasses... I think I have heard something like that before.



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    Default Re: Soliciting advice for unusual build

    Hi Aadams - I think AR is your solution. No latency in the building, things can float, burn etc. Unlimited just check into your nearest holodeck facility.. Peter

    https://voxon.co/technology/

    https://www.360activate.com.au/solut...l-reality.html

    Also there's a lot happening with "Haptics" so look that up...

    https://en.wikipedia.org/wiki/Haptic_technology have fun



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    Default Re: Soliciting advice for unusual build

    If a hardware solution is the only option then here's an alternative method.

    Make the blocks a friction fit into a grid, so that they will stay where they are pushed to vertically, then use an XYZ system underneath to "draw" the walls / features with a roller ball pushing up against the bottoms of the blocks. The ball must be able to move quickly, I can't see why it couldn't push up many blocks per second.



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    Default Re: Soliciting advice for unusual build

    Hi Zorbit - How do the blocks get reset for the next scene? This would be like those pin cushion things you place on an object to capture its shape...Peter



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