The Barbarian Group (Boston, MA)
Biomimetic Butterflies, 2007
Arduino, stepper motors, paper, fabric, rare earth magnets, electromagnets, laser cut wings, sensors
Installation dimensions variable

The Barbarians explore the physical world through a series of mechanical butterflies, made with Arduino (an open-source computing platform), stepper motors, paper, fabric, rare earth magnets, electromagnets, laser-cut wings and sensors that allow for interaction with the physical realm. These little mechanical creatures must be seen in person to be believed.

Biomimetic Butterflies were a result of a cross country collaboration between Barbarian Group members located in San Francisco, Boston, New York, and Los Angeles. The pedestals were constructed by Vince Warner, a fabricator in Seattle.

To make the butterflies, the Barbarians started tossing about different ideas for generative wing design. First up was Voronoi. The Voronoi was decided upon because the vein structure of butterflies resembles Voronoi cells. This algorithm was stretched into two solutions, Angular Voronoi and B-spline Voronoi. The angular version had thin straight Voronoi boundaries and the B-spline version had curves fitted to the negative spaces created from the angular version.

Angular Voronoi

B-spline Voronoi

Next up was flow lines. It is essentially a fluid simulation that shows the direction of the fluid movement not as a grid of vectors but as a solid curved line. This algorithm was also stretched into two versions. The second version mapped circles along the curved lines.

Flowlines

Circle Flowlines

Intersecting lines was probably the easiest to work out. Several lines are thrown into the butterfly wing outline and several can share the same intersection point. These points are augmented with a larger circular shape. The end result was surprising and extremely delicate once laser cut because only the lines were left behind and the solid negative spaces were cut away.

Intersecting Lines

Cracking! The general rule for this piece was to take the wing shape and find its centroid. From here, several line segments would be drawn. The resulting shapes were also analyzed to find their centroids. This was repeated for several iterations and the retrofitted with B-spline curves.

Cracking

And finally, Circle Packing. Randomly sized created circles are randomly placed into the butterfly wing shape. If there is any overlap, that circle is tossed. This is run for a few thousand generations and the result is quite satisfying to see, especially the laser cut paper version.

Circle Packing

The Barbarians then took these seven algorithms and created several prints, each print containing two butterflies from the same family. They also had one set of wings from each family laser cut into heavy stock paper. The individual butterfly wings were then attached to each other with thin fabric strips that would work as a hinge. The wings also had tiny spaces cleared away of laser cuts so tiny rare earth magnets could be sandwiched onto the paper.

The pedestals are hollow to accomodate stepper motors and much larger rare-earth magnets. The stepper motor could be controlled via Processing and Arduino so that it could rotate the large magnet up towards the top of the pedestal. The polarity of the magnets on the butterfly is such that the large magnet pushes the smaller magnets away. Since the butterfly wings are pinned to the pedestal, they take on the appearance of flapping.

The result is a bit creepy. It is plainly obvious that they are not real butterflies. The body, head and legs were nowhere to be seen. You can even see the texture of the paper. And yet, they stir some strange emotion that make one think these paper butterflies want to be free and are strugging against the black metal pins which held them in place. The silence of the mechanisms assists in this illusion because no mechanical noise can be heard.

To assist in this illusion, a webcam is placed at the back of the room. It looks for movement in front of the pedestals and tells the corresponding butterfly to react. This means that if you walk into the room, you see butterfly prints and pinned butterflies in pedestals. As you walk closer to get a better view, the butterfly in the pedestal begins to flap its delicate wings.

More information about The Barbarian Group

Variations

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