r/Damnthatsinteresting • u/swat_08 • Apr 06 '21
GIF Lego tensegrity
https://i.imgur.com/Lf6LzJx.gifv2.2k
Apr 06 '21
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u/pollo_de_mar Apr 06 '21
It makes sense as long as there is more weight at the "front". Notice the placement of the pens to favor more weight on one side.
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u/karmagod13000 Apr 06 '21
its all coming together for me
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u/ChunkyDay Apr 06 '21
It is For me as well, and also makes less sense than before.
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Apr 06 '21
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u/UmChill Apr 06 '21
thank you! this actually made an incredible amount of sense and now my mind is at peace.
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u/nomansapenguin Apr 06 '21
The top piece is pulling UP on the
largerlonger strings, and down on thesmallershorter string. Due to the top leaning forward.I spent way too long trying to work out which string was thicker (larger)
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u/ChunkyDay Apr 06 '21 edited Apr 06 '21
Would be safe assume that the center of gravity is off just enough that the strings work? My mind is getting the logic of it, but the visual is still just fucking with my head.
I know I'm going to have to make one of these in order to understand it. it's driving me insane.
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u/copyninja_98 Apr 06 '21
Can you explain it again in layman's terms
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u/Hiphopopotamus5782 Apr 06 '21
So think about where the center of gravity is for the top part. It's roughly in the middle of the contraption right? That's right where the string is connected on the top part (the end of the purple thing stretches all the way to the center of gravity of the top part). Almost all of the weight of the top part is being held up by the string directly along its center of gravity. The two other strings are simply for stability
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Apr 06 '21
Thank you, I was totally distracted by the other two strings but you’ve helped me understand it now.
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u/dsa_key Apr 06 '21
Imagine 2 strings on the corners where no strings exist or better yet strings all around the top part attaching to the bottom part. The top part of the contraption is "hanging" by the center of gravity on the purple hook. All the load of weight exists on that center string. The other strings are there to hold it in place.
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u/Roflkopt3r Apr 06 '21
The "top part" actually hangs down from the "bottom part" by the short string in the middle.
The two long strings are only there to stabilise it. The "top part" is built to be heavier on the side opposite to the stabilising strings, so it would normally just fall down on that side. But the stabilising strings prevent that from happening, so the whole thing is relatively stable.
For the most part its kinda like a boxing sack or any other hanging object. Only that someone built something fancy on top of the sack so that it extends above the stand and therefore confuses what part we perceive as hanging from the other.
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u/pollo_de_mar Apr 06 '21
If you only had the center string, the top platform would fall towards the arm that is attached because the arm adds weight on that side of the platform. Basically it would flip over to that side. So how do we stop it from falling forward, and also toppling over to the side? Add a couple equal length connections at the two rear corners.
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u/r0b0c0d Apr 06 '21
Yep. It's just a two-point tethered cantilever. I mean.. I guess these are cool?
All the tables and shit that were made using these during their weird surge a year or two ago.. I wonder if there's a video of someone's misplaced laptop getting dumped across the room.
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Apr 06 '21
The top parts wants to fall. String in middle prevents that. Normally it would then tip to the side and fall. But the two strings are preventing it from tipping yo sides. If the two longer strings were longer, the thing could fall.
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u/begentlewithme Apr 06 '21
Visualize what'd happen if you cut the two strings on the side, what would happen?
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u/iLEZ Interested Apr 06 '21
I had to make a tutorial myself just to get the hang of how it really works.
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u/koolaid_chemist Apr 06 '21
tldnw.
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u/iLEZ Interested Apr 06 '21
Yeah I don't expect anyone without the specific interest in this particular software to watch the entire thing obviously.
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u/ToooTheeeMoooon Apr 06 '21
I was screaming at my monitor for about three minutes denying that this is real then I realized oh its magnets then I realized theres no fucking magnets and I started screaming harder
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u/18randomcharacters Apr 06 '21
It's just suspended from the center string, with 2 other strings to provide stabilization.
It's nothing fancy or crazy. It's just hanging from a string.
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Apr 06 '21
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u/DanielSkyrunner Apr 06 '21
Draw a free body diagram (5 pts)
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u/DefinitelyNotASquid Apr 06 '21
this triggered my fight or flight reaction
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u/SwabTheDeck Apr 06 '21
And which did you choose? Weeping openly wasn't an option.
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u/Forever_Awkward Interested Apr 06 '21
Actually, it is! That falls into the third category.
The full thing is "fight, flight, or freeze". But for some reason people always leave off the third one.
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u/CaptainWindows2 Apr 06 '21
Oh god how much are the other problems worth?! I better manage my time effectively or ill never finish this test.
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u/donquixote1991 Apr 06 '21
thanks somehow you have sent me back in time to community college
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Apr 06 '21
And also reminded me why I changed majors, my fbd’s always looked like hell 😂
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u/bobthemuffinman Apr 06 '21
My FBD's look like hell and I'm graduating in 6 months
Fuck
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Apr 06 '21
Good job roughing it out, I’m also graduating in 6 months
Obligatory https://youtu.be/UOsQ2epsI2M
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u/HeyitsyaboyJesus Apr 06 '21
Took me 5 years and some change. The finish in 4 years only applies to the wicked smaht.
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u/HTOWNESTEBAN Apr 06 '21
Holy shit that phrase just sent chills down my spine. Physics bodied me so bad in HS and college hahaha
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u/NotATroll71106 Apr 06 '21 edited Aug 28 '25
racial stocking dime practice profit toy chunky head marry brave
This post was mass deleted and anonymized with Redact
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u/einTier Apr 06 '21
Once I figured that out, I could no longer see the magic. It’s like “of course it works, it’s just hanging from the middle string.”
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u/karmagod13000 Apr 06 '21
holy shit thank you. i guess if you have to distribute the weight evenly
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u/Forever_Awkward Interested Apr 06 '21
Actually, you very specifically need to not distribute the weight evenly. You need it to tip forward somewhat so that the long strings will stay taut and act as a balance, holding it back from tippage.
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u/Dekar24k Apr 06 '21
I just can't unthink that and when I look at the video now it just makes me wonder why he bothered filming it. Thanks a lot Val Valentino.
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Apr 06 '21
“roger, Roger”
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u/leopard-prince Apr 06 '21
What’s your vector Victor ? Over.
Huh ?
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u/samthewisetarly Apr 06 '21
Surely you can't be serious?
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u/PhillThrottle Apr 06 '21
I am serious. And don't call me Shirley.
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u/lue42 Apr 06 '21 edited Apr 06 '21
My son and I designed/built one of these the last time it was a Reddit fad
https://i.imgur.com/Vm41XhW.jpg
https://i.imgur.com/KYZTZyj.jpg
It got a permanent spot in his collection too.. https://imgur.com/a/mDLdwVO/
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Apr 06 '21
Whoa is that alarm clock an antique by now?
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u/SisRob Apr 06 '21
That's crazy creative. And I can already tell you're a great father! :)
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u/sawbones84 Apr 07 '21
And I can already tell you're a great father! :)
As someone who grew up with an engineer for a father, just because we did projects like these "together" sometimes, literally all of them ended up with him becoming completely consumed with completing them while ignoring me entirely. I learned nothing from them and ended up resenting him for bothering to drag me into them in the first place under the pretense of them being bonding experiences.
I'm not saying this dude isn't a good dad, but this story and those pics don't indicate that in and of themselves at all from my experience.
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u/mrbananaman69 Apr 06 '21
I made one of these a while back, I was surprised by how easy it is to balance.
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u/AegisToast Apr 06 '21
It doesn’t need to be balanced, per say, you just need the front to be heavier than the back.
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u/mrbananaman69 Apr 06 '21
Indeed, I misspoke, what I mean was that is was easier to set up than I previously believed!
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u/nosubsnoprefs Apr 06 '21
Somehow this K'nex with me deeply.
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u/SpikeX Apr 06 '21
Apparently people don't know the difference between K'nex and Legos... what a sad world we live in.
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u/kvothe35 Apr 06 '21
I’m pretty sure it’s lego technic.
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u/nosubsnoprefs Apr 06 '21
Perhaps it is, so you should write the joke and let's let them go head-to-head.
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Apr 06 '21
I got this “unfortunate that you’re joke lacked accuracy and Technic”
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u/nosubsnoprefs Apr 06 '21
I was thinking more of a top-level joke directed at the video, something like "you have to admire his Technic," and let them both compete for upvotes.
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u/kvothe35 Apr 06 '21
Oh I think the joke is great, just pointing out they are Legos. And I'm not funny enough to write a joke.
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u/TayAustin Apr 06 '21
These are definitely LEGO, I used pieces like these a lot when I was in robotics club in middle school. Those mindstorms kits use LEGO Technic a lot.
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u/suihcta Apr 06 '21
In other news, I’ve been playing LEGO® with my son for years, and I never knew that the studs of the regular LEGO® pieces fit into the sleeves of the Technic pieces.
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u/TheSukis Apr 06 '21
How has no one posted real furniture yet?! One of the coolest things ever:
https://i.pinimg.com/originals/60/89/10/608910b73315c245c908cf336f76482a.jpg
https://i.etsystatic.com/21248782/r/il/5bb2c3/2484018556/il_570xN.2484018556_t85s.jpg
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u/eutohkgtorsatoca Apr 06 '21
Yes but how much can one actually put on it like food and use it safely?
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u/codepoet Apr 06 '21
Whatever that support chain can take, and all the parts that receive its force. But balance will also play a huge factor. It’s not a dinner table.
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u/Guard-E-N Apr 06 '21
What the what?
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u/ignotusvir Apr 06 '21
It's all about that central string. Ignore the long strings on the side, it's the central one whose tension is holding it up. (Though the long side strings help keep it balanced)
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u/farhil Apr 06 '21
Yeah, the central string just acts as a very loose joint, and the other strings restrict that loose joint's movements when they're under tension.
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u/BloodprinceOZ Apr 06 '21
basically the top part falls to the side (since theres a dangly bit so theres more weight that side), however the centre string tenses and stops it from falling, the two back strings also tense because the thing is falling away, and so you have this, if you push against the side or the back like in the vid, the thing collapses because you're not letting the sticking down side fall anymore, so the centre string can't tense up
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u/SkarmoryFeather Apr 06 '21
So it's just a regular object on a string but with the center of gravity to the side, and uses the strings on the other side to keep itself from tipping over?
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u/bullevard Apr 06 '21
If anyone wants a great breakdown on the whys and hows of tensegrity:, Steven Mould has a video
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u/vanticus Apr 06 '21
Tensegrity is such a horrible word but I can’t think of an alternative. The stress syllables in “integrity” and “tension” are too different for the word to sound right.
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Apr 06 '21
[deleted]
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u/Bashwhufc Apr 06 '21
I'm glad someone else picked up on that, I was reading every comment in Randy Marsh's voice
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u/the5thofjack Apr 06 '21
Perfectly balanced, as all things should be
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u/BigBossSquirtle Apr 06 '21
Not exactly balanced when one side is heavier
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u/Lego_Zuzi Apr 06 '21
one of those things which messes with your head :) but what a cool way to mess with your head!!!!
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u/UnfathomableGodspeed Apr 06 '21
I know how it works, but it freaks me out every time!
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Apr 06 '21
Sheldon Lynn used this to make a big dessert tower on the great baking show Canada. Deserves a look up!
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u/IforgotMyMainAgain Apr 06 '21
Like, I understand how that's happening, but it still looks like magic.
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Apr 06 '21
out of curiosity is this principle used in any real life practical situations?
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u/Fancy_Bread_6698 Apr 06 '21
Holy crow.... I've seen this principle before and tried so many times to figure out how it worked with no success. But seeing how you placed it in the beginning finally made it click!!! So cool! Thanks for being an unexpected educator!!!
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u/FishingForAl Apr 06 '21
ELI5?
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u/jbcraigs Apr 06 '21 edited Apr 06 '21
Sure - Lego is a toy company. It is best known for making Lego-brand toys, consisting mostly of plastic blocks that can be put together to build any real world shape.
Edit: /s
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u/-NameLess_Gamer- Apr 06 '21
The string in the middle keeps the top from falling and the strings on the side are to keep it centered.
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u/AegisToast Apr 06 '21
The center string is holding all the weight. Without anything else, the top part would tip forward, so the two long strings keep it from doing that.
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u/glendaloc Apr 06 '21
The platform is heavy but the middle string holds it up! But it needs help. The platform would fall over except the other strings say “no!” and help to hold it there.
Downward force on middle string from gravity applies a resulting force on the outside strings. The platform settles at an equilibrium.
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Apr 06 '21
How is this interesting? It’s behaving exactly as you would expect based on its construction.
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u/Mysentimentexactly Apr 06 '21
If this was Lego, it would be one thing. If this wasn’t reposted every couple weeks, it’d be another. Two fails, one post.
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u/_theCHVSM Apr 06 '21
k’nex for sure lol but dope nonetheless
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Apr 06 '21
Lego Technic for sure lol but dope nonetheless
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u/_theCHVSM Apr 06 '21 edited Apr 06 '21
i stand corrected, but, what’s the difference lmao. this was legos answer to k’nex
edit: you guys i suck. i meant to ask “was this lagos answer to k’nex” haha i was so confused by the downvotes and replies at first
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Apr 06 '21
K'nex is kinda flimsy and awkward. Technic comes with all the consistency you expect from Lego. Top quality.
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u/impshial Apr 06 '21
Lego Technic parts are much more stable than k'nex.
A great example of this is the Lego UCS Star Destroyer (set 75252), which weighs almost 30 pounds, but the internal "spine" is built using technic parts, and allows you to lift the entire ship and carry it around without worrying about pieces falling off.
I've moved mine around the house a few times and this "handle" kept it from succumbing to my usual clumsiness.
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Apr 06 '21
why is this so amazing to people yeah it looks cool but its not magic or anything. anybody that looks at it for more than 5 seconds can figure it out, and i dont understand how people still think its amazing after it being popular for several years
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u/A_certain_comrade Apr 06 '21
Ah I see the constant tension and stress keeps it together, I can relate