String art is the creation technique of a visual work of art, and the images come from a set of strings that span between the pins. Now, at TU Vienna this work can be delegated to a robot—an example of a complex task that digital fabrication can solve.
The basic idea of string art is simple: hooks distributed on a frame are connected by strings back and forth until they fuse to a perceptible image. In this way,very interesting geometric patterns can be created - in fact,real experts can even create portraits.Traditionally,artists make such images by hand, requiring a highly complex and tedious design process that requires experience and steady hands.
At TU Vienna, this kind of creation of artistic images has now been automated: The computer calculates the optimal thread path from any given image, and the industrial robot takes over the thread's scheduling.
"It's a very interesting problem from a scientific point of view because it's so hard to solve," says Przemyslaw Musialski from the Institute for Discrete Mathematics and Geometry at TU Vienna.Typically, an image cannot be copied exactly this way - after all, the thread method cannot be used to set a single pixel, but to draw a continuous line.It is therefore necessary to find the best possible approximation.
To create the image, a circular frame with 256 hooks is used. "Our calculations have shown that increasing the number of hooks any further improves the final result only marginally," says Przemyslaw Musialski. The thread may be stretched from the right or left side of each hook to the right or left side of any other hook. This way, even with only about 30 threadlines, there are more possible variants than there are atoms in the observable universe—and in order to reproduce a recognizable picture, a much larger number is required.Therefore, finding an algorithm to calculate a thread's path to reproduce a given image as accurately as possible is a big challenge.
However, the mathematical solution to the problem was not enough for the research team. The goal was to produce true "string art" in a fully automated manner.To create circular string art images with a diameter of 63cm, use high-precision industrial robots across a long line of 256 hooks. Even the industrial robot cannot complete this task in a jiffy: Depending on the image, the production takes 2-5 hours and requires between 2 and 6 kilometers of thread.
The research team is part of the Center for Geometry and Computational Design at TU Vienna and it was supported by Peter Wonka's research group at the King Abdullah University of Science and Technology in Saudi Arabia. "Even though our robot produces pretty pictures, our work is of course not an art project," says Przemyslaw Musialski. "Finally, we wanted to show how to solve particularly difficult technical problems.In the string art project, the methods we use will play an important role in digital production in the future."