November 2009

All Four Hooves Leave the Ground is a large scale interactive sculpture that reconstructs the mechanical elements of an analog film projector. The viewer pedals a stationary bicycle to operate a spinning film shutter and drum, on which is displayed an animated sequence of a galloping horse and rider.

At this point, I am actually updating the project's progress as it is happening, as opposed to retroactively: the blog is only a week old, and the project has been on and off for three years. Finishing my MFA in Sculpture at Concordia slowed it down. The primary function of this page is to promote future exhibitions of the sculpture and document its evolution of inspiration, fabrication, and problem solving.

It's looking really sweet, and I'm starting to see light at the end of the tunnel. Phew.

Please click on any image to see it in greater detail.

Many steps throughout the process have not been documented, such as fabricating the 'forked transmission' (the aluminum platform with the perpendicularly mounted gear systems). Another important step not shown was running long aluminum strips through an electric metal bender to make the drum, and bolting the plexi to it.



Five chains have been installed in total. Two of them link the pedals to the Geneva Stop at the rear, passing through a flip-flop hub, also known as a double-sided hub. This may be of interest to bicycle enthusiasts; the hub can accept a fixed gear on one side and a freewheel gear on the other. I am using it to give myself more versatility in being able to adjust gear ratios. The Geneva Stop feeds intermittent power to the forked transmission, which in turn spins the drum and the shutter. Derailleurs have been installed on each chain to regulate tension. Diagonal steel strips have been bolted to the front of the drum support structure to increase stability, which is very necessary in a machine that breaks down into dozens of seperate pieces for storing and shipping purposes. Once I can achieve a consistent tension from one end to another, everything should spin smoothly and I can work on how images mounted on the drum will sync up with holes in the shutter. The 'viewing box' I have installed is still preliminary, and will undergo many modifications. This will include making it light-tight, and vertically adjustable to accommodate riders of different heights.

Eadweard Muybridge and 'The Horse in Motion'

As stated earlier, this project is in part a homage to Eadweard Muybridge and his early photographic experiments which had a huge impact on the development of animation and cinema. Here is a bit of text sampled from his Wikipedia page that describes his work, including the famous Horse Experiment that this sculpture references:

"Eadweard J. Muybridge (April 9, 1830 – May 8, 1904) was an English photographer, known primarily for his important pioneering work, with use of multiple cameras to capture motion, and his zoopraxiscope, a device for projecting motion pictures that pre-dated the celluloid film strip that is still used today.

In 1872, former Governor of California Leland Stanford, a businessman and race-horse owner, had taken a position on a popularly-debated question of the day: whether all four of a horse's hooves left the ground at the same time during a gallop. Stanford sided with this assertion, called "unsupported transit", and took it upon himself to prove it scientifically. Stanford sought out Muybridge and hired him to settle the question. To prove Stanford's claim, Muybridge developed a scheme for instantaneous motion picture capture.

In 1877, Muybridge settled Stanford's question with a single photographic negative showing Stanford's racehorse Occident airborne in the midst of a gallop. This negative was lost, but it survives through woodcuts made at the time. By 1878, spurred on by Stanford to expand the experiment, Muybridge had successfully photographed a horse in fast motion using a series of twenty-four cameras. The first experience successfully took place on June 11, with the press present. Muybridge used a series of 12 stereoscopic cameras, 21 inches apart to cover the 20 feet taken by one horse stride, taking pictures at one thousandth of a second. The cameras were arranged parallel to the track, with trip-wires attached to each camera shutter triggered by the horse's hooves.

This series of photos, taken at what is now Stanford University or in Sacramento, California (there is some dispute as to the actual location), is called The Horse in Motion, and shows that the hooves do all leave the ground — although not with the legs fully extended forward and back, as contemporary illustrators tended to imagine, but rather at the moment when all the hooves are tucked under the horse as it switches from "pulling" from the front legs to "pushing" from the back legs."

March 2008

Here is a charcoal drawing, 8' x 10', I made as a side project to supplement the development of All Four Hooves Leave the Ground. The marks attempt to describe the kinetic action of the sculpture in motion.

Drum center fabrication

Once the aluminum tube had caps welded to the ends and the edges were filed/sanded smooth, it was mounted in a lathe and bored in the center with a 5/8" bit. I commissioned a local machine shop to customize flanges that would be bolted to the ends of the tube, which would in turn be bolted to the machine shaft. This fixes the drum to its shaft in a way that I can still disassemble it for shipping.

Pictured below is the tube sitting in an MDF housing, which I made solely for the purposes of allowing it to sit straight while I drilled and tapped holes in the side. These threaded holes will be where the drum's struts will screw into. Note my rudimentary solution for extending the table of my cheapo drill press: wood blocks, masonite, and newspaper. Work with what you've got!

Drum support structure

Okay, here we are in April 2007. I was working on other projects at the same time, so this is about 6 months after I started. Significant progress has been made: I know that I need a plexiglas drum to float vertically in front of me when I am sitting on the bike, with its center lined up to the height of my eyes. The drum will be 4' wide and 1' think. I acquired a pair of 'pillow block' bearings to hold a machine shaft, which will pass through the center of the drum. It gets mounted to a drum support structure, made out of the same 2" mild steel square tube that the rest is made from.

The silver cylinder pictured is a hollow aluminum tube that I bought and asked the metal tech to TIG weld two flush caps to the ends. I envision the drum struts to be made from aluminum rod (pictured), on which I start the process of tapping threads on to the ends in order for it to screw into the tube. I later abandon this in favour of threaded steel rod. I also have a lens/mirror from an overhead projector (pictured), which may be incorporated into the viewing apparatus.

Built base

Here's an update on the base structure; one can see how I've replaced the wood elements in stages. A technician recommended that I use car muffler clamps from Canadian Tire to attach the cylindrical bike frames to the square steel tubes. I'm starting to get a sense of how much floor space the final machine will take up.

Geneva Stop

The Geneva Stop, a mechanism that transfers continuous circular motion into intermittent circular motion, is the heart of film projectors and mechanical clocks, and therefore also the most important component of this project.

In a film projector, every frame that gets pulled in front of the lens must pause there for a fraction of a second (ie. 1/24, 1/18, etc), in order to be registered by the human eye. The beam of light is interrupted by the shutter in the split second while the next frame is being pulled into place. Therefore, our eyes do not register the time lapse and blurring image in between the frames, and our brain interprets the sequential static images as motion. It is this synchronized relationship of multiple pieces of machinery that I am duplicating. Go here for a great animation explaining how this mechanism works. Go here for more information about film projectors and movie camera technology.

I first built a working model out of MDF, and then was lucky enough to buy a real one from a junk collector. I subsequently fabricated the aluminum housing that holds it together, and modified bicycle gear hubs to mount to the shafts on both the input and output ends of the Geneva Stop.