Art installation “Reflection” is a result of the Signal Calling open challenge, backed in 2019 by PrusaLab. The winning duo, architects Adam Cigler and Petr Vacek were given full access to PrusaLab including all equipment and help from the staff. Six months of hard work later, the installation had its debut during the Signal Festival itself.
“Reflection” consists of dozens of independently moving mirrors. Each mirror is actuated by two servo motors and could tilt in any direction. Each mirror, its motors and a 3D printed supporting frame together form a movable module. Five such modules are attached to CNC-cut plywood panel and connected to a common servo shield, forming an independent cluster, which is controlled by a Raspberry Pi minicomputer. The whole installation includes 18 such clusters, controlled by six interconnected Raspberry Pis.
There is a tailor-made software which not only controls the mirrors but also synchronizes the movement with lights and music. Apart from the site-specific animations compiled in a 3D environment, the mirror wall could be animated with remote-controlled accelerometers. It’s a sophisticated technical system, mirror reflections are continuously morphing and changing. This hypnotic transformation provides a unique audiovisual experience.
This is the first version. Originally, the circular holding frame was printed from a bronze fill filament.
Thanks to parametric 3D modeling, it was easy to change the circular frames to hexagonal, better matching their shape with the mirrors.
“Parametric” means that a 3D model exists as a script, in which you can easily change one parameter and the rest of the geometry recalculates automatically.
However, the first versions were not flawless yet. For example, the actuators were falling out of the construction.
While testing the construction, we realized that for quick assembly, the cluster bottom panel has to fit into the corresponding holes.
We tested the functionality of each 5-module cluster, to find possible errors in the servomotor wiring.
The biggest challenge was to get rid of the mirror fluttering and make the animation smooth. We solved this by optimizing the 3D print parameters and reinforcing the construction with metal fittings.
We couldn’t complete such a large size assembly without help from 16 volunteers. For two weeks, PrusaLab was changed into a dedicated production line.
A static calculation of the steel mainframe dictated a huge maximum load, to prevent the installation from tipping over in a strong wind.
Together we had to use 525 kg of cast iron blocks, formerly serving as counterweights in an industrial lift.
As we had really bad weather during the assembly, a thorough waterproofing of the construction really paid off.
The unique experience attracted more than 60 thousand visitors. Thank you!
Adam Cigler & Petr Vacek
electronics, control software
production & management