3D Zoetrope Uses Illusion To Double The Frames

Although film and animation have come quite a long way, there’s still something magical about that grandaddy of them all, the zoetrope. Thanks to persistence of vision, our eyes are fooled into seeing movement where there is none, only carefully laid-out still pictures strobing under the right lighting.

After four months of research, CAD, prototyping, and programming, [Harrison McIntyre] has built a 3D zoetrope that brings a gif to glorious physical life (video, embedded below). All the image pieces are printed and move under a fancy backlight that [Harrison] borrowed from work. It works essentially the same as a 2D zoetrope, as long as you get the spacing juuuuust right. 360° divided by 20 frames comes out to 18° per frame. So a motor spins the disk around, and every 18°, the light pulses for one millisecond and then turns off until the next frame is in position.

The really interesting thing is that there are actually more than 20 frames at play here. If you follow a single character through the loop, it takes 46 frames to complete the animation thanks to something 3D zoetrope pioneer [Kevin Holmes] dubbed ‘animation multiplexing‘, which in [Harrison]’s example, is easily explained as a relay race in which all runners run their section at the same time, creating the illusion of constant motion.

There’s more than one way to use a 3D printer to create a zoetrope, and we doubt we would have ever thought of this one that squashes four dimensions into three.

10 thoughts on “3D Zoetrope Uses Illusion To Double The Frames

  1. Very neat, though he’s unintentionally confusing his viewers by saying his character only has 46 frames of animation… no, there is 60. He doesn’t count the last 14 frames as the block rises back up to squash the next character. The number of “frames” is always a multiple of the number of segments of the disc – just like the explanation he gives afterwards of how 15 x 4 = 60. Since he has 20 segments, his multiplier is 3. 46 frames with 20 segments would be 2.3.

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