MIT 3D Prints Objects with Lenticular Surfaces

When I was a kid, I really liked optical illusions. I think all kids do: they’re more or less the most basic element to any magic trick; and what kid doesn’t like magic? I mention this because a recent research project at the Massachusetts Institute for Technology’s Computer Science and Artificial Intelligence Laboratory (MIT CSAIL), the results of which were presented last October at the 2021 Association for Computing Machinery’s Symposium on User Interface, has taken the premise of a mass-produced optical illusion with longstanding popularity and transposed it into the 3D printing realm.

You know those images that seem to change from different perspectives? You look at one from a certain angle, it’s the sun rising; walk past it, and it transforms into a full moon in the night sky. (I just made up this particular example, but I’m sure countless versions of it exist, and I probably pulled it from somewhere in my subconscious.) It never occurred to me that this technology had a name, but of course it does: “lenticular”.

Lenticular technology works by creating images out of the combination of many tiny lenses, which display different colors depending on the viewer’s angle. The aforementioned team at MIT — led by Stefanie Mueller, assistant professor at the university’s Department of Electrical Engineering and Computer Science (EECS) — has designed a method for creating 3D objects with lenticular surfaces. Using 3D printing to achieve their objective, the researchers have also made the editing software undergirding the project available for free online.

Funded by the National Science Foundation and the MIT Materials Research Laboratory, the project took about two years to complete. As we have seen with previous 3D printed lenticular objects, the technology of choice was PolyJet from Stratasys. Using a Stratasys J55, it was possible to 3D print both clear lenses (using VeroUltraClear material) and colored patterns (using VeroVivid) onto curved surfaces with sufficient resolution for the application. Parts had to be post-processed, including the removal of support structures and polishing of lenses that were in contact with the supports. 

To demonstrate the technology, the team 3D printed four different objects, each with surfaces containing thousands of lenticular lenses. These included a kettlebell (a type of free weight used for exercising) that shows the user if the object is being held properly; a lampshade exhibiting different greetings depending on whether the person is sitting up in bed — the lampshade says “Good Day” — or lying down — the lampshade says “Good Night”; an earbud case with a variety of multicolored striped patterns; and a shoe printed with a motivational message, which can only be seen by the wearer.

In a statement to the press site for the MIT Materials Research Laboratory, Yunyi Zhu, an EECS Graduate Student at MIT who worked on the project, commented, “Our work opens up the idea of what a physical object can be. It’s part of a larger vision for making dynamic objects that can change their appearance, color pattern, and shape. We address appearance, which is one dimension of the concept of reprogrammable objects.”

I don’t think this work does “open up the idea of what a physical object can be”. At best, this type of research is bound to create more unnecessary consumer garbage. At worst, it’s doing so purely as a byproduct of research that will be useful exclusively to the military: when I first read about the project, and saw that it was done at MIT, I immediately thought, “oh, so this is going to be used to create camouflage objects for the defense sector”, given the university’s historic role in that sector. It also brings to mind the excellent posts on degrowth written by 3DPrint’s Editor-in-Chief, Michael Molitch-Hou.

I brought up the point about optical illusions and magic tricks at the beginning because, just like every kid likes magic, almost every kid also rather quickly grows tired of it and throws out their My First Magic set from the JC Penny Christmas catalog. Basically, there are two routes that the additive manufacturing (AM) world can go from here on out. It can buttress the collapsing decrepit consumer economy so that said economy can haunt the planet just a little longer; or it can be truly disruptive. As a whole, of course, at least in the near future, AM will continue to be both, and probably — like just about everything else — leaning heavily toward the buttressing a dying economy side. Nevertheless, one 3D printed house is still worth a million shimmering 3D printed tchotchkes.