[HN Gopher] Marble Fountain
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Marble Fountain
Author : chris_overseas
Score : 387 points
Date : 2025-11-09 16:26 UTC (6 hours ago)
(HTM) web link (willmorrison.net)
(TXT) w3m dump (willmorrison.net)
| matthewfcarlson wrote:
| This is absolutely brilliant
| dbacar wrote:
| "ramble about marbles"
|
| nice one!
| scubbo wrote:
| A pun? I don't get it, could you explain?
| jwiz wrote:
| Anagram, perhaps.
| dbacar wrote:
| I meant same letters, ramble -> marble
| xnx wrote:
| Stupendous project and video as well! The music is very
| complementary.
| neomantra wrote:
| Amazing on so many levels!! Thank you also for including the
| source.
| Levitz wrote:
| Mesmerizing and beautiful in a simple way, I really like this
| type of thing.
| foltik wrote:
| Be sure to turn on sound for maximum mesmerization.
| CGMthrowaway wrote:
| Mesmerizing is the right word. "I can watch them for hours" was
| the key bit for me - I have always been fascinated how humans
| can stare at a random visual generator for forever, if it's the
| right one.
|
| I think there is an instinct built deep in our lizard brain
| somewhere for this. Humans will happily stare at a fire, or an
| ocean, or a wave in a river, or (sometimes, especially
| children) a TV screen - and all I have worked out why is
| because it is constantly changing in an unpredictable way.
|
| This marble run shouldn't even be unpredictable - clearly the
| paths are fixed and the cadence of balls is regular - but
| somehow it is still mesmerizing.
| ecountry wrote:
| This is magical. Thanks for sharing!
| wxce wrote:
| Beautiful, I wonder what kind of craziness would be possible with
| this, at scale. Whole buildings being printed and assembled block
| by block. Real life Minecraft, if you will
| temp0826 wrote:
| Are procedurally generated rollercoasters a thing?
| sergiotapia wrote:
| Blame! is a manga where in the future humans have robots that
| build, and are controlled by people with Net Terminal Genes.
| Something happens and those humans die leaving the robots
| building non-stop procedurally for eons. By the time our
| protagonist moves about in the world, its said the
| Megastructure reaches from Earth all the way to Jupiter.
|
| Also, the movie Fracture features these cool marble machines.
| https://www.youtube.com/watch?v=Y-v6E9H6nh0
|
| Back when movies were made with unique good scripts and not
| marvel slop.
| 9dev wrote:
| There are serious efforts and working prototypes of printing
| houses. This works surprisingly well, allows construction in
| days instead of months, and shows a lot of promise. It's a
| great rabbit hole to fall into!
| IshKebab wrote:
| Does it though? I have yet to see a 3D printed house that
| would be cheaper than SIP panels.
| lloydatkinson wrote:
| I wish there was a write up of how some of the code works.
| There's a lot of Python in the repo. Looks fascinating, seems to
| use Python to generate OpenSCAD code, I think.
| WillMorr wrote:
| It's specifically using SolidPython2 to generate the models. I
| originally wanted to do a quick code cleanup and have the
| specific math be much clearer but by the time it was working
| that was an absolutely massive undertaking. If I touch the code
| again I'm probably going to refactor the entire codebase and
| use a different 3D engine.
| collingreen wrote:
| This is cool! Great job on the video - Simple voiceover, synced
| music, and the fountain speaks for itself. Bravo.
| MomsAVoxell wrote:
| This is beautiful. It would be amazing to have the tracks
| encode/decode audio, you know? Like, the track of the marble can
| be used to generate different frequencies...
| amenghra wrote:
| There's a Tom Scott music about a musical road in California:
| https://www.youtube.com/watch?v=Ef93WmlEho0
| WillMorr wrote:
| I actually attempted this, the idea of a python script that
| converts a midi track into a marble run is just too good to not
| try. I printed a large drum with different track structures
| inside so I could test various "slopes" by changing the speed
| and it just doesn't work, the balls bounce around too much to
| get an audible pitch. A less rigid material or a larger bearing
| would likely work better but I decided to focus on getting the
| normal version working well.
| smusamashah wrote:
| Did you try changing thickness of rails instead of bumps to
| produce different sounds?
| aitchnyu wrote:
| Is the banking of the curve for a specific velocity?
| stevage wrote:
| It says that the banking is intentionally excessive.
| LandStander wrote:
| This is a great example of a good use case for 3D printers. The
| smooth marble run action combined with the interwoven organic
| forms would be a huge PITA to fabricate with any other method I
| can think of, even if your just making one.
| eschluntz wrote:
| Very cool! I've designed a lot of Hilbert Curve marble tracks,
| using OpenSCAD and python
| WillMorr wrote:
| That sounds super interesting, do you have a link?
| fHr wrote:
| so cool!
| CasperH2O wrote:
| This is really quite interesting and similar to a project I'm
| working on. I've been using procedural generation to generate a
| marble dexterity track similar to a Perplexus. My tools are
| mainly Python, the Build123D library and a 3D printer.
| cyrusradfar wrote:
| I appreciate the work. It's really beautiful and checks so many
| of my "oddly satisfying" boxes as a builder. It seems it hit
| those for you too, obviously.
|
| Separately, the timing of seeing this is uncanny. I've been using
| marble runs to explain probability to my kids and was filming a
| marble run conversion lesson. Seeing this at the top of HN felt
| like someone was reading my minds.
| TealMyEal wrote:
| I would pay silly money for one of those things on my desk
| rwmj wrote:
| Is it printed / sintered in metal?
| hinkley wrote:
| Looks like fiber infused filament.
| randyrand wrote:
| I wonder if you could get it to run silently, or close to it.
| hinkley wrote:
| That guy who makes marble music recently worked out a ball
| funnel that uses inserts in a different material to eat most of
| the noise. But in that case it's also eating momentum as well
| so I'm not sure how that would work for this design. Maybe some
| bushings in the supports to reduce harmonics.
| bigiain wrote:
| Now my brain is doing it's usual "over complicate things to
| the extent a project cannot possibly get started" thing"...
|
| Active noise cancelling. Vibration detectors on oscillating
| parts of the track with LRAs or similar actively driving
| opposing vibrations. Might be able to use whatever the cheap
| active noise cancelling electronics headphones have? Might be
| able to use a high speed camera and video motion
| amplification to work out the best places to deploy it?
| hinkley wrote:
| How you mount things matters a lot, and adjusting shapes to
| prevent harmonics might be something this guy could add to
| his algorithm.
|
| I saved a couple friends in college from getting into
| fights with their downstairs neighbors by finding them milk
| crates to set their speakers on so the bass doesn't all end
| up in the floor. Isolating from the base or making the base
| of TPU could likely help.
| kazinator wrote:
| Designers of marble fountains who don't use computing to design
| the paths run into reliability issues: sometimes balls derailing
| out of their track. They have to observe the contraption,
| identify problems (balls getting jammed up or jumping out) and
| then guess at the root causes and make manual adjustments.
|
| That's the thing here: he has it running for hours presumably
| without any ball jumping out.
|
| Most of the tracks consist of two rails, so the ball has two
| contact points. I'm no physicist but it seems like the goal would
| be to have ideally nearly equal forces at the two contact points
| at all times during the ball's descent. In other words, the track
| has to be perfectly banked so that the gravity and centripetal
| acceleration vector are balanced by a normal vector perpendicular
| to the rails. During a derailment, the ball has to lift away from
| one of the two contact points, so the normal force must have
| dropped to zero.
| WillMorr wrote:
| It's actually much weirder than that: banking changes the axis
| of rotation and thus kills the rotational inertia. The tracks
| bank super aggressively in order to prevent the ball from
| accelerating too much and hopping the track. This is part of
| why the descent is so smooth and all the balls move at more or
| less the same speed.
|
| Also to be fair the final system does lose a ball every 30ish
| minutes. The tuning was largely me staring at the run or taking
| a video trying to catch where they get lost. Instead of hand
| tuning I would just update the generator and print another one.
| I'm considering closing the loop with a camera but that would
| be a whole new project.
| sixtyj wrote:
| For roller coasters there is a software for simulation. It is
| imho similar situation compared with balls in your Marble
| Fountain
|
| https://www.nolimitscoaster.com/
|
| First, I thought about Ansys or CATIA software but I couldn't
| find any module specialized for simulation of balls.
|
| But I think that people from those companies could help as
| well and participate in simulation as an interesting usecase.
| (These software are expensive for personal projects.)
| djmips wrote:
| Well except for this is SIM only whereas the OP (WillMor)
| is making them for real with a 3D printer!
| sixtyj wrote:
| My point was that these software could help to find weak
| parts in trajectory - so instead of trying to figure it
| out by looking where balls are too quick to fall from the
| ride - you can simulate it. I saw real tramway simulation
| done in Ansys.
| hinkley wrote:
| Maybe it's the color and this would look better in a brighter
| shade, but I hate it. It looks wrong. Malignant.
| hinkley wrote:
| I bet this would look baller with green rails and brown
| supports. Also might help with losing the balls visually as
| they get to the bottom. The visual noise makes them harder to
| track.
| underdeserver wrote:
| It looks like Bones from Hades 2. Beautiful, and super cool.
| bix6 wrote:
| Super cool! I would love to see a white / clear one with LEDs.
| Rainbow road :)
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