9 ms·

Topology-disturbing objects: a new class of 3D optical illusion (2017)

127 points by aesthesia 7y ago

Pelam 7y ago
"Keywords: ... anomalous object, impossible object, ..." Will somebody please call SCP already ;)
- zaarn 7y ago
  Uncounted number of dead D-class personal and MTF squads later, it's concluded that it's safe.
jacknews 7y ago
Cool. STLs? Would love to print a couple of these for my kid's show-and-tell in class edit: found some , search "illusion" on thingiverse, not "topology" :) eg, https://www.thingiverse.com/thing:3169391 https://www.thingiverse.com/thing:3169391
- maaaats 7y ago
  My whole collection is here: https://www.thingiverse.com/Matsemann/collections/matsemanns-ambiguous-cylinders https://www.thingiverse.com/Matsemann/collections/matsemanns... Do it, I have shown these to various school classes. They have been popular everywhere, from primary school to universities!
louis8799 7y ago
forget the math, just enjoy
FatalLogic 7y ago
Video is the best way of showing how strange these can appear - https://i.imgur.com/g5Ot0rH.gif https://i.imgur.com/g5Ot0rH.gif Source - https://www.thingiverse.com/Matsemann/collections/matsemanns-ambiguous-cylinders https://www.thingiverse.com/Matsemann/collections/matsemanns...
- yorwba 7y ago
  Your source link helped me find where it had been posted on HN by the creator of those models before: https://news.ycombinator.com/item?id=18307573 https://news.ycombinator.com/item?id=18307573 The top reply to that comment pointed out that you can rotate the models in GitHub's viewer: https://github.com/Matsemann/impossible-objects/blob/master/3dfiles/arrow/filledarrow_whole.stl https://github.com/Matsemann/impossible-objects/blob/master/... https://github.com/Matsemann/impossible-objects/blob/master/3dfiles/circlesquare/circleinnersquare_2x2.stl https://github.com/Matsemann/impossible-objects/blob/master/...
  - bonoboTP 7y ago
    I never knew it's so simple to embed 3D visualizations. How does GitHub do this? How can I do this on my own website? What's the name of the tech I should google?
    - TFortunato 7y ago
      My guess is you want to start by looking at three.js --I've been on teams using it for a robotics debugging tool with a web interface, and it's definitely a nice library to work with!
- JetSpiegel 7y ago
  https://i.imgur.com/g5Ot0rH.mp4 https://i.imgur.com/g5Ot0rH.mp4 300kb video instead of 6MB GIF
ur-whale 7y ago
OBJ file anyone ?
- deleted 7y ago
  [deleted]
- lisper 7y ago
  https://www.thingiverse.com/Matsemann/collections/matsemanns-ambiguous-cylinders https://www.thingiverse.com/Matsemann/collections/matsemanns... That link has STL, not OBJ, but maybe that's good enough.
  - ur-whale 7y ago
    Very neat, thanks. Loading one of these things in blender and rotating it around is really worth doing, and it's totally weird: when you rotate most 3D objects interactively, you can get a good grasp of their shape, but these things feels like they are specifically designed to prevent that from happening.
    - lisper 7y ago
      > they are specifically designed to prevent that from happening Yes. Exactly! :-)
    - matsemann 7y ago
      Yeah, the weeks I spent making that collection was quite mind-bending, hehe.
yarg 7y ago
This is old enough that the year (2017) should be in the title. Also, the optical illusion isn't really 3d since it relies on a single point perspective - it'll show up on camera, but if you see it with two eyes you'll see the actual structure. Now for a real 3d optical illusion, look at the hollow face illusion - not on video - find a real life instance of a depth reversed face. Your brain has circuitry specifically optimised for facial recognition, and what you're seeing so confuses your mind that it breaks depth perception. It will actually appear as if a static object is turning to follow you around the room.
- ColinWright 7y ago
  > .. if you see it with two eyes you'll see the actual structure. I'm interested to know if your statement based on personal experience. I have some of Sugihara's work, and what you claim is not the case. If you view it from a sensible distance (over 30 cms or so), and even if you know how it works, the illusion is still effective. Of course the illusion disappears if you view it from radically the wrong direction, or from less than 10 cm, but based on my experience, your claim seems over-stated.
  - yarg 7y ago
    Even then, it's still not 3d - it's based on lighting and a lack of contrast - it's a projection based illusion that requires distance so that the variations between the two two-dimensional projections are not enough that your brain re-comprehends what it's looking at. I'm not saying it isn't cool - there's something quite neat about the fact that the brain misinterprets what it's seeing as the nearest known 2d icon. But it's not 3-dimensional.
deleted 7y ago
[deleted]
caleb-allen 7y ago
Is this the same type of illusion? https://www.youtube.com/watch?v=oWfFco7K9v8 https://www.youtube.com/watch?v=oWfFco7K9v8

127 points by aesthesia 7y ago

Pelam 7y ago

"Keywords: ... anomalous object, impossible object, ..." Will somebody please call SCP already ;)

zaarn 7y ago
Uncounted number of dead D-class personal and MTF squads later, it's concluded that it's safe.

jacknews 7y ago

Cool. STLs? Would love to print a couple of these for my kid's show-and-tell in class edit: found some , search "illusion" on thingiverse, not "topology" :) eg, https://www.thingiverse.com/thing:3169391 https://www.thingiverse.com/thing:3169391

maaaats 7y ago
My whole collection is here: https://www.thingiverse.com/Matsemann/collections/matsemanns-ambiguous-cylinders https://www.thingiverse.com/Matsemann/collections/matsemanns... Do it, I have shown these to various school classes. They have been popular everywhere, from primary school to universities!

louis8799 7y ago

forget the math, just enjoy

FatalLogic 7y ago

Video is the best way of showing how strange these can appear - https://i.imgur.com/g5Ot0rH.gif https://i.imgur.com/g5Ot0rH.gif Source - https://www.thingiverse.com/Matsemann/collections/matsemanns-ambiguous-cylinders https://www.thingiverse.com/Matsemann/collections/matsemanns...

yorwba 7y ago
Your source link helped me find where it had been posted on HN by the creator of those models before: https://news.ycombinator.com/item?id=18307573 https://news.ycombinator.com/item?id=18307573 The top reply to that comment pointed out that you can rotate the models in GitHub's viewer: https://github.com/Matsemann/impossible-objects/blob/master/3dfiles/arrow/filledarrow_whole.stl https://github.com/Matsemann/impossible-objects/blob/master/... https://github.com/Matsemann/impossible-objects/blob/master/3dfiles/circlesquare/circleinnersquare_2x2.stl https://github.com/Matsemann/impossible-objects/blob/master/...
- bonoboTP 7y ago
  I never knew it's so simple to embed 3D visualizations. How does GitHub do this? How can I do this on my own website? What's the name of the tech I should google?
  - TFortunato 7y ago
    My guess is you want to start by looking at three.js --I've been on teams using it for a robotics debugging tool with a web interface, and it's definitely a nice library to work with!
JetSpiegel 7y ago
https://i.imgur.com/g5Ot0rH.mp4 https://i.imgur.com/g5Ot0rH.mp4 300kb video instead of 6MB GIF

ur-whale 7y ago

OBJ file anyone ?

deleted 7y ago
[deleted]
lisper 7y ago
https://www.thingiverse.com/Matsemann/collections/matsemanns-ambiguous-cylinders https://www.thingiverse.com/Matsemann/collections/matsemanns... That link has STL, not OBJ, but maybe that's good enough.
- ur-whale 7y ago
  Very neat, thanks. Loading one of these things in blender and rotating it around is really worth doing, and it's totally weird: when you rotate most 3D objects interactively, you can get a good grasp of their shape, but these things feels like they are specifically designed to prevent that from happening.
  - lisper 7y ago
    > they are specifically designed to prevent that from happening Yes. Exactly! :-)
  - matsemann 7y ago
    Yeah, the weeks I spent making that collection was quite mind-bending, hehe.

yarg 7y ago

This is old enough that the year (2017) should be in the title. Also, the optical illusion isn't really 3d since it relies on a single point perspective - it'll show up on camera, but if you see it with two eyes you'll see the actual structure. Now for a real 3d optical illusion, look at the hollow face illusion - not on video - find a real life instance of a depth reversed face. Your brain has circuitry specifically optimised for facial recognition, and what you're seeing so confuses your mind that it breaks depth perception. It will actually appear as if a static object is turning to follow you around the room.

ColinWright 7y ago
> .. if you see it with two eyes you'll see the actual structure. I'm interested to know if your statement based on personal experience. I have some of Sugihara's work, and what you claim is not the case. If you view it from a sensible distance (over 30 cms or so), and even if you know how it works, the illusion is still effective. Of course the illusion disappears if you view it from radically the wrong direction, or from less than 10 cm, but based on my experience, your claim seems over-stated.
- yarg 7y ago
  Even then, it's still not 3d - it's based on lighting and a lack of contrast - it's a projection based illusion that requires distance so that the variations between the two two-dimensional projections are not enough that your brain re-comprehends what it's looking at. I'm not saying it isn't cool - there's something quite neat about the fact that the brain misinterprets what it's seeing as the nearest known 2d icon. But it's not 3-dimensional.

deleted 7y ago

[deleted]

caleb-allen 7y ago

Is this the same type of illusion? https://www.youtube.com/watch?v=oWfFco7K9v8 https://www.youtube.com/watch?v=oWfFco7K9v8