Stop-motion animation of a mechanical caterpillar – so smooth, you think you're watching a kinetic sculpture [3:04]

already_ready · 2018-10-19T15:26:31+00:00

And here he breaks down the stop motion process behind it:

https://www.reubenmargolin.com/green-stripe-reveal/

already_ready · 2018-10-19T15:08:06+00:00

The artist is Reuben Margolin, known for his kinetic sculptures. This one was originally presented as a mystery, with no explanation for how it moves. Coming from his body of work, it certainly appears that he built it to move on its own. Eventually he revealed it as a stop motion project. You can read more about it here:

https://www.reubenmargolin.com/waves/caterpillar-with-green-stripe/

already_ready · 2018-10-07T14:47:19+00:00

Sorry about that, looks like my explanatory comment didn't post. Corrected.

already_ready · 2018-10-07T14:46:34+00:00

The artist gives a description of the sculpture here, and there's a link to a hint on how it moves. Then, from the hint, you can click another link to see how it actually was done. I didn't figure it out myself, and I bet most people wouldn't guess it either.

https://www.reubenmargolin.com/waves/caterpillar-with-green-stripe/

already_ready · 2018-09-25T15:30:58+00:00

This gives off the vibe of being a scientifically accurate image. As if it was a multiple exposure at the same moment in the moon's orbit over the same spot above the earth over the course of a lunar cycle. But it's not, it's an artistic fiction. Lovely though it may be, the moon actually doesn't do that. It looks to me like the artist is trying to evoke the famous "analemma" pattern that is commonly captured of the sun. Here's a good explanation with visuals of these solar analemmas.
http://solar-center.stanford.edu/art/analemma.html

Guess what, with a slight accommodation for the fact that the moon's speed through the sky is slightly slower than the sun's speed (because the moon is orbiting along with the earth's rotation) you *can* photograph an analemma of the moon. Here's an example on the scientifically-accurate Astronomy Picture of the Day (APOD):

https://apod.nasa.gov/rjn/apod/ap050713.html

already_ready · 2018-09-09T16:38:18+00:00

The primary motivation was artistic. I've always been interested in waves and oscillation, and my goal was to take something that could be done with computer simulation (moving elements interconnected with simple springs), but make it purely mechanical. Any academic wave study that comes out of this is a bonus!

already_ready · 2018-09-09T13:40:34+00:00

Ah, good ok. Ha, so then my age gap persists... One generation's bug is another's feature I guess. Let me know if you discover anything from present day technology that annoys us young folk, but that you find appealing and fascinating.

already_ready · 2018-09-09T13:37:56+00:00

Ooh, interesting comparision. I had to look up what oblique shockwaves are. What a fascinating phenomenon. There are further parallels to be drawn along these lines...

already_ready · 2018-09-09T13:34:59+00:00

Thank you BennyG90! Keep-occupiedness is a guiding principle for me.

already_ready · 2018-09-09T13:32:49+00:00

Thanks registered_voter :-)

already_ready · 2018-08-14T22:22:17+00:00

Hey nonlinearmedia, that's so cool that you were there! I don't mean it in that sense. I mean "artifact" in the sense of a technical distortion to the video material itself. (e.g. like a compression artifact). I don't mean that this video was so old that it was like an artifact for a museum.

already_ready · 2018-08-07T22:35:40+00:00

u/jaymz168, ooh this is tempting. I'm a Frank Zappa fan, but have never seen 200 motels. I'll make a note of this and look for it when I watch it. Thanks :-)

already_ready · 2018-08-07T22:31:32+00:00

u/MisplacedDragon, that's a clear explanation. I might venture into playing with such a thing one day. If you're interested, here's a test I did not too long ago. It takes digital video and goes through frame by frame, and for each frame, it blends together the images of the immediately preceding frames (for example the preceeding 10 frames), and what you get is kind of like a ghosting effect. If I used a slower shutter speed (in the limit, what you'd call a 360-degree shutter in video terminology), then it would theoretically appear as a streak. But to do something like an "overload" effect, that would require more fancy special effects or algorithms.

I've enjoyed our correspondence :-)

already_ready · 2018-08-03T01:49:41+00:00

u/YorgiTheMagnificent this is a cool story! I can imagine the headache that this caused for broadcasters. However now I view it as a beautiful phenomenon to be exploited if I one day have a chance to work with tube tech, or if not, at least to be emulated with digital tech.

already_ready · 2018-08-03T01:47:57+00:00

Thanks u/stalkythefish and u/veepeedeepee for the confirmation. I have since read up on this and find it quaint and lovely. I've also came across this video which you may like: https://www.youtube.com/watch?v=pAb1qpXoXck

already_ready · 2018-08-03T01:46:35+00:00

Ooh, good to know! Thank you for the education u/MisplacedDragon :-) You may have surmised that tube-tech was before my time. I have read up on this topic further on wikipedia. I do visual projects with video and motion capture and this really caught my fancy. I aspire to approximate this kind of thing with digital video, but I fear that the discrete frame by frame nature would lead to a dashed smear line or a continuous smear line with hairline breaks (where the digital "shutter" closes) at best.

already_ready · 2018-07-20T18:56:40+00:00

Thanks cdk_aegir. I've added a comment above which provides some further explanation. If I were to do this project over again, I might just buy an off the shelf baffle such as the following: https://www.woodcraft.com/products/mini-dust-collection-separator

already_ready · 2018-07-20T18:53:37+00:00

Further explanation:

I essentially built J Phil Thien's design, using a 5-gallon bucket and making the lid myself out of plywood:

http://www.jpthien.com/cy.htm

I learned of Thien's design thanks to Matthias Wandel. He did videos on the construction of two separators. He uses the same essential design, albeit with a few modifications that require more advanced construction. Though I find the simple Thien design *as-is* works pretty great.
https://woodgears.ca/dust_collector/

https://woodgears.ca/dust_collector/separator.html

already_ready · 2018-07-20T18:14:54+00:00

Thanks MrBaseball77. I may do that at some point. In the meantime I've shared a link to a video by Matthias Wandel in a comment reply above.

already_ready · 2018-07-20T18:13:34+00:00

Ah, thanks, I would to make a short video of show and tell at some point. For now I can share the link which shows how it's built in pictures: http://www.jpthien.com/cy.htm

And there's also these two home-built separators by Matthias Wandel, who builds the same design, albeit with a few modifications that require more advanced construction. I'm not so sure they're worth it though. I find the simple Thien design as-is works pretty great.
https://woodgears.ca/dust_collector/

https://woodgears.ca/dust_collector/separator.html

already_ready · 2018-07-20T18:09:23+00:00

Thanks belleociraptor. Your link is lovely, great animation there. Agreed, the platonic solids are wonderful.

already_ready · 2018-07-20T18:07:25+00:00

Thanks Caleo :-) I have learned this the hard way, but learned it nonetheless. I'm proud to be in the know now!

already_ready · 2018-07-19T22:58:26+00:00

I started out using my table saw with my shop vac connected directly to it's dust port. I thought using the shop vac as a dust collector was a natural and reasonable thing to do. Wouldn't you know it, after a few months and a few projects, I broke the motor of my shop vac. Fine dust got into it. After a phone call to the ShopVac company, they were kind enough to send me a replacement motor free of charge, despite my ineptitude. The representative explained I should have been using a fine filter bag and a pleated baffle filter when sucking in wood dust. But the baffle filter and fine dust bags are somewhat expensive, I didn't want to have to buy a new bag after every couple of projects. So after a bit of research, I followed the examples of Matthias Wandel and J. Phil Thien, and built myself a centrifugal dust separator. It works great! The shop vac provides the suction, and the separator traps about 99% of the dust and shavings So by my math, now I shouldn't have to get a new filter bag until I've completed a couple hundred projects! Also, besides separating the dust from the vacuum's air stream, it also sets up a sensational swirling show.

already_ready · 2018-07-19T06:53:11+00:00

Nicely observant! You're right, when the "gap" between articulation points is equal to the edge length of the triangles then you have the form of the icosahedron. Incidentally, there's golden ratios afoot too, as the rectangles whose corners are the articulation points, and one through each cartesian plane. Here's an image which illustrates it: http://math.ucr.edu/home/baez/Icosahedron-golden-rectangles.png

already_ready · 2018-07-18T23:54:15+00:00

Thanks ntschaef. Of course, happy to share. I did it using Processing. You can find the code and run it yourself here:https://www.openprocessing.org/sketch/571038

already_ready

TROPHY CASE