As part of the special report on open-source design published in issue 948, Domus approached Carlo Ratti to write an op-ed on the theme of open-source architecture. He responded with an unusual suggestion: why not write it collaboratively, as an open-source document? Within a few hours a page was started on Wikipedia, and an invitation sent to an initial network of contributors. The outcome of this collaborative effort is presented below. The article is a capture of the text as of 11 May 2011, but the Wikipedia page remains online as an open canvas—a 21st-century manifesto of sorts, which by definition is in permanent evolution.
The contributors to this article included Paola Antonelli, Adam Bly, Lucas Dietrich, Joseph Grima, Dan Hill, John Habraken, Alex Haw, John Maeda, Nicholas Negroponte, Hans Ulrich Obrist, Carlo Ratti, Casey Reas, Marco Santambrogio, Mark Shepard, Chiara Somajni, Bruce Sterling

Open Source Architecture (OSArc) is an emerging paradigm describing new procedures for the design, construction and operation of buildings, infrastructure and spaces. Drawing from references as diverse as open-source culture, avant-garde architectural theory, science fiction, language theory, and others, it describes an inclusive approach to spatial design, a collaborative use of design software and the transparent operation throughout the course of a building and city's life cycle.

Cooking is often hailed as an early form of open source; vernacular architecture—producing recipes for everyday buildings—is another form of early lo-fi open-source culture, openly sharing and optimising technologies for building. A contemporary form of open-source vernacular is the Open Architecture Network launched by Architecture for Humanity, which replaces traditional copyright restrictions with Creative Commons licensing and allows open access to blueprints. Wider OSArc relies on a digital commons and the shared spaces of the World Wide Web to enable instantaneous collaboration beyond more established models of competition and profit. Traditional architectural tools like drawings and plans are supplemented and increasingly replaced by interactive software applications using relational data and parametric connectivity.

OSArc is not only involved with production; reception to a given project—critical, public, client, peer-related—can often form part of the project itself, creating a feedback loop that can ground—or unmoor—a project's intention and ultimately becomes part of it, with both positive and negative consequences. OSArc supersedes architectures of static geometrical form with the introduction of dynamic and participatory processes, networks, and systems. Its proponents see it as distinguished by code over mass, relationships over compositions, networks over structures, adaptation over stasis. Its purpose is to transform architecture from a top-down immutable delivery mechanism into a transparent, inclusive and bottom-up ecological system— even if it still includes top-down mechanisms.

OSArc relies upon amateurs as much as experienced professionals—the genius of the mass as much as that of the individual—eroding the binary distinction between author and audience. Like social software, it recognises the core role of multiple users at every stage of the process—whether as clients or communities, designers or occupants; at its best, it harnesses powerful network effects to scale systems effectively. It is typically democratic, enshrining principles of open access and participation, though political variations may range from stealth authoritarianism to communitarian consensualism.

Open Source Architecture revolutionises every step of the traditional building process, from brief-building to demolition, programming to adaptive reuse, including the following:

Funding
New economic models, exemplified by incremental microdonations and crowd-funding strategies like Sponsume and Kickstarter, offer new modes of project initiation and development, destabilising the traditionally feudal hierarchy of client/architect/occupant. Financing of private projects increasingly moves to the public domain, offering mass rather than singular ownership, whereas funding of public projects can be derived from more flexible, responsive frameworks than simple levies or taxation. OSArc has particular appeal for builders outside the mainstream economy, such as squatters, refugees and the military.

Engagement
Traditional developments deploy engagement programmes in which the community is consulted on incoming developments, with blunt tools such as focus groups, which often result in lack of representation and input, or at worst can result in NIMBYism. With crowd-funded models, forms of engagement are built into the process, enabling a kind of emergent urbanism in which use of space is optimised on terms set by its users. This reclamation of people's power can be seen as a soft, spatial version of Hacktivism. OSArc can suffer some of the organisational drawbacks of open-source software, such as project bifurcation or abandonment, clique behaviour and incompatibility with existing buildings.

Standards
Standards of collaboration are vital to OSArc's smooth operation and the facilitation of collaboration. The establishment of common, open, modular standards (such as the grid proposed by the OpenStructures project) addresses the problem of hardware compatibility and the interface between components, allowing collaborative efforts across networks in which everyone designs for everyone. Universal standards also encourage the growth of networks of non-monetary exchange (knowledge, parts, components, ideas) and remote collaboration.

Design
Mass customisation replaces standardisation as algorithms enable the generation of related but differentiated species of design objects. Parametric design tools like Grasshopper, Generative Components, Revit and Digital Project enable new user groups to interact with, navigate and modify the virtual designs, and to test and experience arrays of options at unprecedented low cost—recognising laypeople as design decision-making agents rather than just consumers. Opensource codes and scripts enable design communities to share and compare information and collectively optimise production through modular components, accelerating the historical accumulation of shared knowledge. BIM (Building Information Modelling) and related collaboration tools and practices enable cross-disciplinary co-location of design information and integration of a range of platforms and timescales. Rapid prototyping and other 3D printing technologies enable instant production of physical artefacts, both representational and functional, even on an architectural scale, to an ever-wider audience.

Construction
The burgeoning Open Source Hardware movement enables sharing of and collaboration on the hardware involved in designing kinetic or smart environments that tightly integrate software, hardware and mechanisms. Sensor data brings live inputs to inert material and enables spaces to become protoorganic in operation; design becomes an ongoing, evolutionary process, as opposed to the one-off, disjointed fire-and-forget methodology of traditional architecture. Operating systems emerge to manage the design, construction and occupancy phases, created as open platforms that foster and nourish a rich ecosystem of "apps". Various practices jostle to become the Linux, Facebook or iTunes of architectural software, engaging in "platform plays" on different scales rather than delivery of plans and sections. Embedded sensing and computing increasingly mesh all materials within the larger "Internet of things", evolving ever closer towards Bruce Sterling's vision of a world of spimes. Materials communicate their position and state during fabrication and construction, aiding positioning, fixing and verification, and continue to communicate with distributed databases for the extent of their lifetime.

Occupancy
OSArc enables inhabitants to control and shape their personal environment—"to Inhabit is to Design", as John Habraken put it. Fully sentient networked spaces constantly communicate their various properties, states and attributes—often through decentralised and devolved systems. System feedback is supplied by a wide range of users and occupants, often either by miniature electronic devices or mobile phones— crowd-sourcing (like crowd-funding) large volumes of small data feeds to provide accurate and expansive real-time information. Personalisation replaces standardisation as spaces "intelligently" recognise and respond to individual occupants. Representations of spaces become as vital after construction as they were before; real-time monitoring, feedback and ambient display become integral elements to the ongoing life of spaces and objects. Maintenance and operations become extended inseparable phases of the construction process; a building is never "complete" in OSArc's world of growth and change. If tomorrow's buildings and cities will now be more like computers—than machines—to live in, OSArc provides an open, collaborative framework for writing their operating software.

References
— R. Botson, R. Rogers, What's Mine is Yours: The Rise of Collaborative Consumption, HarperCollins, New York City 2010
— M. Fuller, U. Haque, "Urban Versioning System 1.0", in Situated Technologies Pamphlet Series, Architectural League of New York, New York City 2008
— J. Habraken, Supports—An Alternative to Mass Housing, The Architectural Press, London 1972
— U. Haque, Open Source Architecture Experiment, 2003-05
— D. Kaspori, "A Communism of Ideas: towards an architectural open source practice", in Archis, 2003
— K. Kelly, Out of Control: the rise of neo-biological civilization, Perseus Books, New York City 1994
—C. Leadbeater, We-think: The Power of Mass Creativity, Profile Books, London 2008
—Nettime mailing lists: mailing lists for networked cultures, politics, and tactics
—Open Building Network / Working Commission W104, "Open Building Implementation" of the CIB, The International Council for Research and Innovation in Building and Construction (meets in a different country every year since its first meeting in Tokyo in 1994)
—C. Price, R. Banham, P. Barker, P. Hall, "Non Plan: an experiment in freedom", in New Society, no. 338, 1969
—M. Shepard (editor), Sentient City: Ubiquitous Computing, Architecture, and the Future of Urban Space, MIT Press, Boston 2011
—B. Sterling, "Beyond the Beyond", blog on Wired Magazine