Most 3D prints have one look and stick with it. A team at MIT CSAIL just showed off prints that change color when you twist a knob, with no LEDs, no electronics and no paint anywhere. The technique is called ShiftLens, and the physics behind it is old enough that you have almost certainly held it in your hands before.
The idea borrows from lenticular printing, the effect behind those novelty cards that flip between two pictures as you tilt them. A ShiftLens object is printed as two stacked parts. The top layer is a sheet of tiny linear lenses printed in transparent material. Underneath it sits a patterned layer printed in alternating colors, lined up so each stripe of color hides behind its own lens.
What makes this different from a novelty card is that the object itself moves. Instead of you tilting your head, a built-in mechanism slides the lens layer sideways across the pattern layer by a fraction of a millimetre. Each lens suddenly magnifies a different color stripe, and the whole surface flips hue at once. That mechanism can be a knob, a switch or a roller, anything that shifts the two layers relative to each other. The demo people latched onto was a bottle: close the container properly and the band around it changes color, so the object tells you at a glance that it is sealed.
Want to experiment with the concept? The researchers built their design tool inside Rhino and have not released it publicly yet, so treat this as a build to explore rather than a file to download. The ingredients are all ordinary multi-material 3D printing, though: a clear PETG or clear PLA lens layer printed at a fine layer height, a two-color pattern layer beneath it, and a sliding fit loose enough to move but tight enough to stay flat. Start small. A 40 mm flat test tile with roughly 1 mm lens pitch will teach you more about lens alignment in one print than an entire afternoon in CAD.
Try it on your printer. If your machine can handle two materials, or even a manual filament swap at a set layer, you already have everything you need to attempt a first lenticular tile tonight. If you would rather have someone dial in the tolerances for you, the Flarelab team prints and tests multi-material parts every week and can help you get from sketch to working prototype. Browse the shop and the workshop builds at flarelab.com and tell us what you would make change color.
Frequently asked questions
What is a lenticular 3D print?
It is a print made of two layers: a transparent sheet of narrow linear lenses on top, and a striped multi-color pattern underneath. Each lens shows one stripe at a time, so shifting the layers changes which color you see.
Do I need a multi-material 3D printer?
It helps, because the pattern layer needs at least two colors. You can approximate it on a single-extruder machine with a scripted filament change at a specific layer, though alignment is harder and results vary.
Which filament works for the lens layer?
Clear PETG is the usual starting point because it stays glossy and prints reliably. Clear PLA also works. Fine layer heights and a smooth top surface matter far more than the brand of filament you choose.
Can I download the ShiftLens files right now?
Not yet. The MIT CSAIL team built their design tool for internal use in Rhino and has not published a public version, so makers recreating the effect are currently modelling the lens and pattern layers themselves.
Source: 3D Printable Lenticular Indicators on Hackaday, covering the ShiftLens research from MIT CSAIL. Rewritten for beginners by the Flarelab team.
Originally published at flarelab.com.
Top comments (0)