thumb|200px|Another sample sheepElectric Sheep is a collaborative volunteer computing project that uses a genetic algorithm to animate and evolve fractal flames. The generated animations are downloaded to networked computers and displayed as a screensaver. Created by programmer and software artist Scott Draves in 1999, the project harnesses the idle processing power of hundreds of thousands of computers to form a distributed render farm.

As users watch the screensaver, they can vote on their favorite animations. These votes act as the fitness function for the genetic algorithm, allowing the network to "breed" the most popular designs into new, evolving animations. Operating at the intersection of artificial life, generative art, and distributed computing, the project is widely recognized as a pioneering work of digital art. It has been exhibited at major museums including Prix Ars Electronica and the MoMA.

History and origins

Electric Sheep was created in 1999 by software artist and computer scientist Scott Draves. The visual foundation of the project relies on the "fractal flame" algorithm, an extension of iterated function systems (IFS) which Draves created and released as open-source software in 1992.

The name "Electric Sheep" is an homage to the 1968 science fiction novel Do Androids Dream of Electric Sheep? by Philip K. Dick. Draves used the title to mirror the architectural nature of the project: when a user's computer goes to sleep, the screensaver activates and the machine begins rendering (dreaming) the fractal movies (the sheep).

  • Non-linear functions: Instead of relying strictly on affine transformations, fractal flames use non-linear equations, resulting in the organic, sweeping curves seen in the screensaver.
  • Logarithmic tone-mapping: The density of the fractal is rendered using a logarithmic scale rather than a linear one, which prevents the images from appearing overexposed and preserves the glowing, wispy details.
  • Color mapped by structure: Structural data from the math is mapped to color palettes, allowing the algorithms to assign complex gradients to the twisting filaments.

Technology and distributed network

Because rendering high-quality, anti-aliased fractal animations requires massive amounts of processing power, the software acts similarly to the SETI@home project. It links the idle computers of all the users running the screensaver into a single, global supercomputer.

Network architecture

When a user installs the screensaver, their computer becomes a node in a peer-to-peer and client-server hybrid network. A central server directs the network, assigning specific frames of a fractal animation to individual computers. Each client computer calculates its small piece of the larger animation, uploads the data back to the server, and then downloads the completed video files to display on the screen.

The Genetic Algorithm

The project functions as an ongoing artificial life experiment. The server stores a "flock" of animations at any given time. The "DNA" or genotype of each sheep consists of roughly 130 parameters—mathematical variables that dictate the color, motion, and shape of the fractal flame. The resulting video animation is the phenotype. To address this, the computer-generated sheep parameters and movies are distributed under a Creative Commons Attribution Noncommercial (CC-BY-NC) license, while parameters manually created and uploaded by advanced users are licensed under Creative Commons Attribution (CC-BY).

Business model and version history

In its early iterations, Electric Sheep was entirely open-source and relied strictly on donated bandwidth and server space. As the project grew to over 500,000 active monthly users, the server costs necessitated a shift in the business model. The project began utilizing a portion of the network's distributed computing power to render commercial animation projects, the sales of which helped keep the servers running. Furthermore, with the release of the 2.7.x and 3.x series, the project adopted a freemium model. While the standard screensaver remained free, users could purchase a "Gold" subscription to receive high-definition (HD) sheep and uncompressed video formats. Because portions of the server code and HD data were no longer entirely free under this new model, the package was subsequently removed from the main Debian repository.

Artistic impact and exhibitions

Although it operates globally as a screensaver, high-definition captures of the Electric Sheep have been heavily exhibited in the contemporary art world. Media theorist Mitchell Whitelaw praised the project in his book Metacreation, describing the evolved visuals as "luminous, twisting, elastic shapes, abstract tangles and loops of glowing filaments."