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The Charon Zoetrope is pictured against a red sky, with all of its skeletons around the edge visible in silhouette form.
Charon at Burning Man festival in 2011 © Mitzi Peirone

Reimagining the zoetrope

An installation from the 2022 Greenwich+Docklands International Festival is a life-sized, vertical zoetrope that uses time-honoured engineering principles to display a stunning three-dimensional short animation. Neil Cumins investigates the science behind this supersized kinetic sculpture, Charon, by artist Peter Hudson and crew.
A zoetrope, with the image displayed inside an animation of a lion leaping at a horse in a circus environment.

A modern replica of a Victorian zoetrope © Andrew Dunn

During the first 10 days of September 2022, the skyline of Canning Town’s Limmo Peninsula looked a little different to usual. Each night, a vertical zoetrope almost 10 metres in height, lit by strobes and powered by human volunteers, showed a 3D animation depicting the ferryman from Greek mythology, Charon. This art installation arrived from Nantes, on its tour of art festivals around Europe, and was originally devised for Nevada’s Burning Man festival in 2011.

Zoetropes are one of the earliest form of animations, dating back to the 1800s. Historically, they consist of a cylinder with a progression of images inside and slots to peer through. As the wheel spins, the rapidly changing sequence of images gives the viewer the illusion of movement, with the slots preventing the images from blurring into one. While at first based on strips of paper with sequences of illustrations (not unlike a flipbook), later developments would go on to use photographs and even sculptures.

Most zoetropes are toy-sized, intended for entertainment long before the world of film arrived; but in recent years, a handful of artists have built larger scale installations designed to wow audiences. However, it is by no means a common artistic medium. Mat Collishaw, one of the Young British Artist group, has exhibited several 3D zoetropes, some up to three metres across (coincidentally, his 2014 zoetrope All Things Fall was produced in collaboration with Factum Arte – see ‘Technology to recreate artworks’, to read about some of the company’s other work). But the zoetropes designed by San Francisco visual artist Peter Hudson are some of the world’s largest, measuring up to almost 10 metres in diameter, and have been displayed at well-known festivals from Burning Man to the UK’s Secret Garden Party.

The zoetropes designed by San Francisco visual artist Peter Hudson are some of the world’s largest, measuring up to almost 10 metres in diameter, and have been displayed at well-known festivals from Burning Man to the UK’s Secret Garden Party.

A diagram describing the Victorian-designed mechanism co-opted by Hudson to get the Charon zoetrope to work.

Image reproduced from

Mechanical inspirations 

The Victorians had an impressive influence on everything from engineering to entertainment – and sometimes both at once. In 1868, Henry T Brown published a book called Five Hundred and Seven Mechanical Movements, including detailed illustrations of kinematic concepts important for engineers, from rotating pulleys to pendulums.

A 1908 edition included detailed illustrations of concepts such as epicyclic gear trains – also called planetary gears, today used in everything from cars to 3D printers and pencil sharpeners – and capstans, the rotating machines used by sailors to haul weights (such as anchors). It also included a diagram demonstrating how to convert an oscillating semicircular frame into rotary motion. This showed a device that can convert oscillating motion into rotary motion (see image). A semicircular piece (A) attached to a lever working on a fulcrum (a) is attached to the ends of two bands (C and D). The bands run around two pulleys, loose on the shaft of the flywheel (B). One of the bands (C) is open, and the other (D) is crossed. Pawls attached to the pulleys engage with ratchet-wheels on the flywheel shaft when piece A turns in either direction, producing continuous rotary motion.

Fast-forward to the start of the 21st century, and this diagram became a source of inspiration for Peter Hudson. He had spent the noughties creating a series of stroboscopic sculptural zoetropes, depicting everything from recurring universes to people swimming. However, Hudson’s previous projects had all been horizontal zoetropes, and he had something more ambitious in mind for his next design, which he was due to create for the 2011 edition of Burning Man festival.

Rites of passage

Hudson’s idea for the new project was to create an interactive depiction of Charon, the Greek mythological ferryman, who carried away departed souls across the river Styx to the afterlife. This was to tie in with the theme of that year’s festival, rites of passage, and Hudson chose to focus on the final rite of passage: death. The work was to be funded by a grant from the festival and multiple fundraising campaigns, with over 100 volunteers pitching in to construct the zoetrope. The zoetrope would be powered by audience members pulling ropes to create torque (rotational force). After exceeding a certain speed, the 3D animation would become apparent. The choice of ropes was a nod to cathedral belfries, where ropes are used to ring a bell.

A night time shot of the Charon Zoetrope being operated by volunteers - the skeletons are visible as they are lit by a strobe.

The central structure of Charon visible from below. Participants can be seen pulling on the ropes to generate torque in the far right of the image © Trey Radcliff Haron

A vertical zoetrope of this scale had never been attempted before, and logistical challenges immediately arose from this Ferris wheel-esque design. Most important was the need to translate linear force from people pulling ropes to torque that could drive the rotational motion of the vertical zoetrope. The solution lay in Brown’s Victorian handbook, and the aforementioned diagram. It depicted a semicircular piece attached to a lever resting on a fulcrum, with two pulleys connecting it to a flywheel. A continuous rotary motion is maintained as the semicircular piece turns first one way and then the other. For aesthetic reasons, Hudson employed the same principle, but used 12 30-centimetre-diameter drums with custom clutch bearings. With this setup, the force produced by volunteers pulling ropes would be translated into torque to drive rotation of the zoetrope. This spinning motion, when allied to strobe lighting, creates an effect akin to a three-dimensional motion picture, and requires a rotational speed of 20 rpm (revolutions per minute).

Overcoming challenges 

Hudson’s first horizontal zoetrope had a central rotational axis sandwiched by two tapered roller bearings, requiring only one support point. By contrast, some of his later horizontal zoetropes were supported by idler wheels, but each extra load point increased drag. Instead, Charon’s entire rotating structure would rest on a single hub (with four bearings). This vertical zoetrope would require both left and right support points and two tapered roller bearings on each side – all correctly aligned in space.

Furthermore, early prototypes relied on components from bicycle sprockets, which repeatedly failed because of the sheer torque being generated by Charon’s human participants. Eventually, an equivalent component from a Raptor quad bike was sourced, which could handle over 1,000 Newton-metres of torque. Another early setback involved the use of manila hemp rope. Not only did this struggle to grip each eight-inch custom-machined aluminium drum satisfactorily, but it also rubbed against itself creating friction and drag that contributed to premature wear. The solution involved encasing each rope in a repurposed fire hose, which had the twin benefits of increasing grip and minimising abrasion. Similarly, sharp internal hex-nut edges on the directional guide pulleys were discovered to be shredding the ropes. These hex-nut edges were sanded down, with Teflon rope glides employed to reduce wear.

A close up of the model skeletons that appear to row on the Charon giant zoetrope.

The model skeletons spaced around the zoetrope, each adopting a unique pose to give a sense of the rowing motion © Mitzi Peirone

Next, attention turned to the skeletons that would comprise Charon’s zoetropic effects. Each model was made from polyester resin and urethane foam, with the skulls, femurs and ulnas custom-cast from foam and polyester resin. The more fragile torso components were purchased from a medicalgrade vendor since there was no need for these to move. The team invented a malleable and posable armature that the bones could be situated around, in what would become their final position, with a pivot point at the hips. Next, modelling software was used to create an animation that involved each skeleton adopting a unique pose, to contribute to the sense of movement as the wheel rotated.

Motion picture 

In motion, the results of this modelling software and skeletal positioning are spectacular. Accompanied by the sound of a tolling bell, flame-coloured lights flicker around two Gothic A-frame archways with the wheel centrally mounted between them. A dozen participants tug on ropes that additionally serve to ring the bell. Once the six pairs of ropes are being pulled at a suitable speed, a strobe is activated that reveals the animation of the skeletons inside the wheel as they ‘paddle’ towards the unknown using wooden oars, creating an otherworldly effect as it towers above spectators. The frame itself – like much of Charon – is manufactured from I-Beam steel, contributing to a gross shipping weight of over 8,000 kilograms. Once fully erected, the zoetrope reaches nearly 10 metres tall.

The spinning wheel has a diameter of almost nine metres, with 20 spokes each supporting an animated skeleton, in various rowing positions. The wheel rests inside two double-strut A-frame support arches with cross bracing at both ends.

Building tension 

Assembling Charon takes up to five days, partly because each side of the wheel has to be in perfect alignment. Two parallel points must be exactly square and level, within one millimetre of each other, to align the hub bearings. The team achieves these tolerances by using a five-beam laser. The assembly and transportation process has been further optimised by numbering every item, allocating it a dedicated place within its transportation containers, and ensuring each item is unloaded in the order of assembly. For instance, skeletons are attached to the wheel at 180-degree, then 90-degree, then 180-degree positions, maintaining wheel balance and preventing its weight becoming unequal. A variety of custom dollies, high-density polyethylene glides and platforms are used for moving components along with a forklift truck, a 10-metre-tall variable reach lift, a cherry picker, and a crane.

The entire structure is accommodated in two 24 metre shipping containers, and the installation manual alone extends to over 50 pages, with a team of 10 people employed to assemble Charon. Disassembly is quicker, taking three to four days, at the end of which a crew of six people is allocated portions of a grid pattern to check Charon’s former location for misplaced hardware. When in the desert they even use magnets to identify and rescue any components that have become submerged in the ground. Nothing can be left behind from such a meticulously engineered assembly, especially one that is constantly touring around the world. 


This article has been adapted from "Reimagining the zoetrope", which originally appeared in the print edition of Ingenia 92 (September 2022).


Neil Cumins


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