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\author{Erik de Bruijn\\
e.debruijn@uvt.nl\\
Dept. of Information Management\\
Faculty of Economics and Business\\
University of Tilburg, The Netherlands\\
\\
Thesis for the degree of Master of Science\\
\\
Supervised by:\\
Prof. R. O'Callaghan\\
TiasNimbas Business School, University of Tilburg\\
\\
Additional advisors: \\
J. de Jong, Erasmus University\\
and\\
E. von Hippel, MIT Sloan School of Management
}

\title{On the viability of the open source development model for the design of physical objects\\
Lessons learned from the RepRap project}
%\subtitle{Master Thesis}
\date{09/06/10}

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\pagenumbering{roman}

\begin{abstract}
 While open source software development has been studied extensively, relatively little is know about the viability of the same development pattern for physical objects. The present research reviews the literature on open source and user innovation communities followed by a case study and survey of the RepRap community in which both software and physical objects are collaboratively designed and freely revealed. Patterns observed in the RepRap community provide insight into how the distributed development of physical objects could become a more general phenomenon. Several important trends are identified, such as the increased digitization of design and manufacturing processes and availability of more affordable development and prototyping tools.\\
% The manufacturing capability distributed among RepRap users mitigates some of the logistic drawbacks of distributed development of physical objects.\\ 

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{\bf Keywords:} Open source development model, open design, distributed innovation, flexible manufacturing
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\chapter*{Preface}
\section*{Acknowledgements}
First of all, I'd like to thank my friends and family for their support throughout this process. Most notably I am thankful to my loving wife Esther for her patience and encouragement. I am thankful to my supervisor and my colleagues. To professor O'Callaghan, for finding the time to supervise me, for his support and his valuable feedback. I'd like to thank Jeroen de Jong of Erasmus University for proof-reading early versions of this work, for frequently providing advice and in general being a great mentor. I'd like to thank Eric von Hippel for his friendly encouragement and inspirational guidance. Moreover, his seminal work in user innovation and open source communities provide a critical foundation for this thesis.

During my research, many people have provided important insights, put me into contact with the right people or otherwise have enabled me to do this work. I wholeheartedly thank the whole RepRap and related communities, of which many have taken the time to provide information through the survey and otherwise. I'd like to thank the many people that have provided encouragement and welcomed me to their homes, hackerspaces and labs. In particular I'd like to thank Benjamin "Mako" Hill, Zach ``Hoeken`` Smith, Bre ``Bre`` Pettis, Adrian Bowyer and Michel Bauwens. The  organizers of conferences where I had the privilege to speak which were the furtile soil for discussions and development of ideas that are now incorporated in this work. To Siert Wijnia, for being a good friend and companion to the several conferences. To Siert and to Martijn Elserman, for involving me in yet another adventure in open source 3D printing.
% Interviewees: Geral Barnett, ... TNO, Kees S... Somatech, etc.
Additional thanks go out to Eric von Hippel and the MIT Sloan School of Management for subsidizing trips to New York City and MIT, Cambridge which has allowed me to conduct key interviews for my research and to EIM for providing additional funding that allowed me to do this work.\\
\\

% It really is a remarkable experience collaborating with you all.
% The many people who have welcomed me to their attics in FabLabs and Hackerspaces. To the organizers of conferences where I had the privilege to speak which were the furtile soil for discussions and development of ideas that are now incorporated in this work. To Siert Wijnia, for joining me on the quest to inspire as many people as possible.
% Family and friends who have supported me throughout the process.
% Finally, my thanks go out to everyone in the RepRap and related communities. It really is a remarkable experience collaborating with you all.


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\chapter{Introduction}\label{Ch:Introduction}
\pagenumbering{arabic}
\section{Motivation}
% (Eerder aankondigen wat het RepRap)
Our information and communication infrastructures are evolving rapidly. As observed by Shapiro and Varian (1999), even if information is produced at a high fixed cost, it can be reproduced to high fidelity at negligible incremental cost. This hints at an enormous potential diffusion of valuable works. It stresses the importance of a better understanding of the provisioning and distribution of information based goods in society. With the costs of communication falling, new forms of collaboration are emerging. One of these forms, called open source development, typically involves a large set of individuals and/or organizations to share the workload \citep{Haefliger2008}  while the public good properties of the outcome are preserved \cite{Osterloh2007}.

Open source software development has attracted significant scholarly attention \citep{Spaeth2008}. A lot of research is devoted to explaining the characteristics of open source software development as being different from a traditional, more top-down development paradigm. The successes of projects like Linux, Apache and Firefox not only highlight the merit of the development methodology but also its real-world significance, robust functioning in the marketplace and its value creation potential \citep{Krogh2003}. The non-exclusive nature of the output of the open source development process is associated with value spill-overs and at the same time enabling organizations and individuals to innovate faster and at a lower cost.

Studying the viability of the open source development methodology is specifically relevant because it has been shown that it addresses several important issues concerning creation of public goods
% nog een andere paper ook!
 \citep[p. 119]{Benkler2006TWON}, and does so in a sustainable way \citep{Osterloh2007}. Software and other information products can be considered non-rival, because distribution typically does not involve a loss of the sender. Distribution, because if its digital encoding is virtually free.

In the literature, open source development of physical objects, so called open design, is hardly touched upon. In open design, information such as schematics, bills of materials and assembly instructions are freely revealed. Prevalence of open source in physical design projects with some degree of visibility is still very modest when compared with software. Data collection on open design projects by \citet{Balka2009} resulted in 85 listed projects by August 2009, which is a relatively small number when compared to over 380,000 open source software projects on SourceForge in the same year\footnote{SourceForge is a popular open source project hosting solution. In February 2009 there were 380,000 projects listed. From: \url{http://sourceforge.net/about}}.
% Open source enters the world of atoms: A statistical analysis of open design
%by Kerstin Balka, Christina Raasch, and Cornelius Herstatt.
%First Monday, Volume 14, Number 11 - 2 November 2009
%http://www.uic.edu/htbin/cgiwrap/bin/ojs/index.php/fm/article/viewArticle/2670/2366Cross reference with: http://sourceforge.net/projects/?q=avr 
When broadly defined, open design predates open source software by centuries \citep[e.g.][]{Allen1983,Nuvolari2004}. Yet the distributed nature of open source development had not emerged in open design as it has in software. The low number of hardware related projects leads observers to think that it is not a viable domain for open source production. Viability of any mode of production is determined by the way work is organized. Through an in-depth study of the RepRap project, in which both software and hardware development are present, this thesis will help remedy this knowledge deficit. This thesis will investigate what influences the viability of this mode of development for physical designs. This will be done through a study of the RepRap community, a community that develops an open design of a machine that can fabricate physical copies of digital designs. 

The aim of the RepRap community is to develop a machine that can fabricate physical objects of arbitrary shape, including copies and improvements of its own parts. The fabricated objects are based on digital content and the owners of the RepRap machines can download, improve and redistribute designs via the internet, as well as have each of the owners fabricate physical instances of such objects. Like many open source software communities, the RepRap community isn't geographically concentrated. \label{RepRapIntroduction}
%The RepRap project is also one of the first distributed open design projects that employs the open source development model.

\begin{quotation}
\citet[p. 121]{Benkler2006TWON} remarks that \textsl{``[t]he highly distributed capital structure of contemporary communications and computation systems is largely responsible for this increased salience of social sharing as a modality of economic production in that environment. By lowering the capital costs required for effective individual action, these technologies have allowed various provisioning problems to be structured in forms amenable to decentralized production based on social relations, rather than through markets or hierarchies.''}\end{quotation}

Typically, the more mature open source software communities are accompanied by for-profit organization. This is common because of the value being generated by the ecosystem as a whole, allowing organization to capture some of it. Likewise, the RepRap community is encompassed by an ecosystem of user-founded businesses, manufacturing service providers and user innovators\footnote{Hybrid ecosystems having both user innovators and manufacturers have been studied by \citet{ShahTripsas2007UserEntrepreneurship} and \cite{Baldwin2006}. The dual role within a single organization is studied by \cite{Block2010UserAndMfg}.}. 
%User innovators switching to dual role of mfg.+user inno. 
% example of user entrepreneurship originating not from individual user innovators (as described by Baldwin et al., 2006, and Shah and Tripsas, 2007)
%  

% 
% The Geography of Crowdfunding - christian@catalini.com
The high growth rate of the community and its surrounding ecosystem and the rapid diffusion of distributed production resources provide the primary means for distributed physical prototyping and production. It is of high importance to investigate the implications of the availability of low-cost physical production resources and which role they play to extend social production beyond the virtual world.
%for innovating communities who employ an open source development model.

\section{Problem statement and research questions}
Because the development model of open source software apparently can produce highly successful output, it is very important to see if this model can be applied to a wider range of problems. \citet{Weber2004} also emphasizes the importance of this question, stating that \textit{"[t]he open source process has generalizable characteristics, it is a generic production process, and it can and will spread to other kinds of production. The question becomes, are there knowledge domains that are structured similarly to the software problem?"}
He goes on to say that:
\textit{"The key concepts of the argument - user-driven innovation that takes place in a parallel distributed setting, distinct forms and mechanisms of cooperative behavior regulated by norms and governance structures, and the economic logic of "antirival" goods that recasts the "problem" of free riding – are generic enough to suggest that software is not the only place where the open source process could flourish."}

Open source software development has been studied quite extensively for various reasons  \citep{SpaethKroghCharThatPromRes2007}. However, by comparison, very few studies of open source development outside of software have been done. The literature on user innovation communities includes studies of highly distributed communities producing software. It also includes studies of such communities developing and exchanging physical resources.
% In the case of open-source software, innovations can be produced and distributed essentially for free on the Web because software is information rather than a physical product. In the case of sports the innovation, however, innovation in equipment are embodied in a physical product that requires physical production and distribution and involves economies of scale. The result for physical products generally is that innovation can be carried out by users and within user communities, but production and diffusion of products incorporating those innovations is usually handled by manufacturing companies.

Yet, these communities mostly lack the spacial distribution and frequent interactions that characterizes many software projects. This appears to be a result of the logistics of physical items and the resulting difficulties in transferring physically embodied knowledge\footnote{\citet[p. 86]{VonHippel2001FlossToSports} concludes that in contrast with open source software, innovation in equipment are embodied and distribution requires physical production and distribution and involves economies of scale. The result for physical products generally is that innovation can be carried out by users and within user communities, but production and diffusion of products incorporating those innovations is usually handled by manufacturing companies.}. Based on the existing studies, is not evident whether this type distributed development is viable at all. This study of the RepRap project, not only provides a strong indication that it is viable, it also tries to identify factors that influence viability and discusses the generality of these findings.\\

The stated problem will be addressed by answering the following research question:
\subsection*{To what extent is the open source development model also viable for the design of physical objects?}

I will start addressing this question by referring to research that explains the viability of open collaborative innovation projects in general. This mode of development is not specific to software or physical products  \citep{EvH_DI_intro2005}. I will show that the conditions for viability are met for the specific case of the RepRap community. In the case description I will also show that while the tangible dimension is relatively unique, RepRap has many things in common with typical OSS community.
% TBD: Show this more extensively!!

\subsubsection{Question 0: What is open source?}
Before addressing the actual research problem, it needs to be clear what I mean when we use the words "open source". This question will be answered through a review of the literature on open source. After defining it in the literature review in chapter \ref{Ch:Theory}, the two main research questions will be addressed. 
% TBD: In the discussion on the generality of the findings, we will focus on whether the studied case has characteristics that are held in common  with other open source communities.
After having described open source which Open Source Software and open design have in common, the first research question focuses on differences between the two and their impact.

\subsubsection{Question 1: What are differences between open source software development and open development of physical objects?}
This question will first be addressed mostly from a theoretical perspective. Differences with respect to lifetime, modularity, supply chains, replication, cost structure and patent law were highlighted by \citet{AbdelkafiBleckerRaasch2009}. To further explore the differences the creation, transfer and diffusion of innovations in each area will be compared statistically through the survey.

\subsubsection{Question 2: How are drawbacks of the physical nature of open design addressed in the RepRap project?}
Because frequent exchanges of physical innovation are common among members of the RepRap community, these will qualitatively be examined. In particular, we will identify resources and cultural factors that facilitate these interactions. These resources include knowledge, infrastructural tools, software tools and physical equipment. Cultural aspects have to do with norms and rules present in the community and the way in which feedback is given. 
% these too, have an impact but are thought to be held in common...
The case study will reveal how the tools and culture, taken together, enable distributed physical prototyping. The statistics from the study reveal to what extent the drawbacks of the physical embodied hardware compared are mitigated in the RepRap project. 




\section{Methodology}

% \subsection{Approach}
% between the way in which the open source software and hardware...
For any detailed comparison between the way in which open source software and hardware are developed,  it is valuable to adopt a theoretical perspective that generalizes from features that are unique to either of the models. Through the literature review, three theoretical perspectives are found to be appropriate. These frameworks will be evaluated in the literature review.
% framework -> theoretical perspectives.
The context for addressing the research problem will be provided by both the literature on open source software and the more general research models applicable to open source innovation. I will draw from the latter research models because they have proven to be applicable to software development without being limited to software alone. They have frequently been used to study collaborative development of physical products too.

To restrict the areas in which I will find differences, I will look into a single community which develops both software and hardware to solve the same problem. The emphasis is not on differences between distinct OSS and OD communities. For an overview of various OD communities and their differences see \citet{Balka2009}.

Using a single community has an important research benefit. With regards to the product this will limit variations such as whether it's a functionality or aesthetics is dominant; the RepRap project's main product is a functional design of a machine employing both software and physical designs. On the other hand, differences that result from whether parts of the product design pertain to a software module or a physical part become more salient when these other parameters are constrained.

It also restricts producer variations. Among other things, I will learn whether individual participants have different perceptions and motivations, employs different methods and encounter different problems while dealing with either software or hardware.

\subsection{Case study}
To understand how open source development can function outside of the more familiar context, a case study helps answer the "how" and "why" questions \citep{Lather1992,Robottom1993,Ellis2008,Yin2002}. In this case it will be used to better the understanding of participants' actions and the context of their behavior.

Since the interest is in understanding something more general than the case, adoption of an instrumental case study methodology is deemed appropriate. The case, as an instance of the studied phenomenon, plays merely a supportive role to understanding the phenomenon. The case is looked at in depth, its context scrutinized, its ordinary activities detailed, and because it helps the researcher pursue the external interest. The case may or may not be seen as typical of other cases. \citep{Stake1995}

Because the choice between an instrumental or intrinsic case study is not obvious, this deserves some clarification. Stake (Ibid.) uses the term intrinsic and suggests that researchers who have a genuine interest in the case should use this approach when the intent is to better understand the case. It is not undertaken primarily because the case represents other cases or because it illustrates a particular trait or problem, but because in all its particularity and ordinariness, the case itself is of interest. The purpose is not to come to understand some abstract construct or generic phenomenon \citep[pp. 548-549]{Baxter2008}.

% ! Introduce the case. 1 sentence.
As mentioned in section \ref{RepRapIntroduction} this thesis includes an in depth case of the RepRap project. The case is very unique and interesting in itself for several reasons: the fact that open source development is practiced beyond its familiar scope, the physically embedded nature of the exchanged innovations, the frequency of these exchanges, the rapid growth of the community and, finally, the individual members' access to resources that even few firms have. On the face of it, the generality of the findings from such a case study seem to be very limited. After a more in depth review of the literature, however, it appears that the theory even predicts the activity that is observed. Given the good fit with the already well-established analytical framework, it seems a mistake to consider it as \textit{sui generis}, an isolated case that does not fit into a broader encompassing framework. That this particular case has properties that are salient does not imply that the properties are fundamentally new. Recent developments, however, allow  a much larger group of individuals to participate in this extended scope of open source development.

\subsection{Survey}
The survey provides insight into adoption, creation, transfer and diffusion of both software and hardware innovations and the importance of location and infrastructure for diffusion of innovations. Under the conditions that hold for the RepRap community, there is a certain impact of tangibility of hardware (having to do with the embodiment and logistics). This empirical data is used to determine the nature and significance of these effects.

Empirical data was gathered by administering a survey among users and developers in the community. Participation was limited to only those who build and/or operate open source 3D printers. This excludes a potentially larger group of people that does interact with the community but isn't building their own machines, however it allows more in depth questions pertaining to the use of the machines. Invitations to participate were posted on various blogs, forums and social media platforms that community members frequently access.


\section{Thesis outline}
This thesis is structured as follows (depicted in figure \ref{fig:outline}). The \hyperref[Ch:Introduction]{current chapter} introduces the research problem and explains how it is addressed. Chapter \ref{Ch:TheoreticalFoundation} serves as the theoretical foundation by defining open source and by reviewing the relevant literature. Concepts most important to address the research problem at hand will be identified here. The case study of the RepRap community and its development process is provided in chapter \ref{Ch:CaseStudy}. Following an introduction of the community, an emphasis will be placed on the concepts that were identified in the literature review. Chapter \ref{Ch:Survey} will contain a qualitative analysis of the RepRap contributors to determine differences between the software and hardware with respect to creation and diffusion of innovations. Then, in chapter \ref{Ch:Theory2Practice}, will revisit the theoretical part and confront it with the empirical findings from this study. Finally, chapter \ref{Ch:Conclusions} concludes this thesis with a discussion of both the theoretical and empirical findings and suggestions for further research.
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 \caption{Outline of this thesis}
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\chapter{Theoretical foundation}\label{Ch:TheoreticalFoundation}
For a proper analysis of the case, a good definition of concepts like open source, open source communities and projects is pertinent. In addition, to meaningfully contribute to the existing body of literature, it needs to be clear how the case aligns with the existing theory and research frameworks. This will be done, respectively, in the first and second paragraphs. The third and final paragraph, justifies the appropriateness of the theoretical perspective which was adopted.
%The findings, with respect to which theoretical perspective which is adopted will be most appropriate are summarized in the third and final paragraph of this chapter.
% framework -> perspective

\section{Terminology and definitions}
For this analysis it is important to clearly define what open source is. Open source has several distinct but related meanings. It is used to denote a practice regarding the licensing of intellectual property of software and other creative works. In addition, it is often referred to as a development methodology and in some cases as a collaborative strategy between users and user-firms. Moreover, open source communities are examples where these collaborative strategies and the development methodology are being practiced. This section elaborates on these meanings.

\subsection{Defining open source}
% USEFUL PAPER: \citep{Gacek2002ManyMeaningsOfOS} discusses what is common in open source projects.

Formally, for software to be called open source its license has to conform to the Open Source Definition (OSD) as outlined by the Open Source Initiative \footnote{See \url{http://www.opensource.org/docs/osd} for a full copy of the OSD.
% OR APPENDIX nn
}. Most notably, the OSD implies that software has a license that permits modification, and must requires free redistribution of the software under the same license. The licenses compatible with the Open Source Definition are mostly based in copyright law since this type of intellectual property law is most applicable to software, which is the area where free and open source practices emerged. 

Perhaps the most important function of the open source licenses is to ensure non-exclusive access to the intellectual property. This inverted application of intellectual property law has many implications. From the perspective of the individual developer, it helps to prevent that their work is appropriated. Moreover, reuse and improvement of open sourced products can be carried out without needing to ask for permission. This somewhat reduces transaction costs, reduces the barriers to contribute and reduces duplication of effort. Moreover, potential benefits encourage a more modular approach, which is often considered a good development practice for maintaining high quality standards even for systems with a high complexity.

It should be noted that the OSD does not lend itself well to also cover physical product licenses, as these may need to also draw on other legal domains. Copyright law can only be used to protect implementations of ideas, and not the ideas themselves. In this way, the license will apply to copies of design documents and design files, but the design itself is not copyrighted. Moreover, the non-exclusive nature of the design files does not preclude the existence of patents that impose limitations to the use of the files to manufacture it, however the same could be said for software patents. It is difficult to assess the impact of interactions between these legal domains and it is further complicated by the fact that there are legal differences between the various different regions. Most of these issues are still unresolved, however some new development are underway. 

% Rather than creating a new license, some open source hardware projects simply use existing, open source software licenses.
% 
% Additionally, several new licenses have been proposed. These licenses are designed to address issues specific to hardware designs. In these licenses, many of the fundamental principles expressed in open source software OSS licenses have been "ported" to their counterpart hardware projects. Organizations tend to rally around a shared license. For example, Opencores prefers the LGPL, FreeCores insists on the GPL, Open Hardware Foundation promotes "'copyleft' or other permissive licenses", the Open Graphics Project uses a variety of licenses, including the MIT license, GPL, and a proprietary license, and the Balloon Project wrote their own license. New hardware licenses are often explained as the "hardware equivalent" of a well-known OSS license, such as the GPL, LGPL, or BSD license.
% 
% Despite superficial similarities to software licenses, most hardware licenses are fundamentally different: by nature, they typically rely more heavily on patent law than on copyright law. Whereas a copyright license may control the distribution of the source code or design documents, a patent license may control the use and manufacturing of the physical device built from the design documents. This distinction is explicitly mentioned in the preamble of the TAPR Open Hardware License.
% 
% Noteworthy Licenses
% 
%     * The TAPR Open Hardware License: drafted by attorney John Ackermann, reviewed by OSS community leaders Bruce Perens and Eric S. Raymond, and discussed by hundreds of volunteers in an open community discussion
%     * Balloon Open Hardware License: used by all projects in the Balloon Project
%     * Although originally a software license, OpenCores encourages the LGPL
%     * Hardware Design Public License: written by Graham Seaman, admin. of Opencollector.org
% From: http://www.servinghistory.com/topics/open_source_hardware::sub::Licenses

Recently a version of the Open Source Hardware (OSHW) Definition was drafted. Yet it is in a very early and volatile state and mostly borrows from the OSD. Some open source licenses that pertain to hardware have been developed, but none of them are very mature. Moreover, the lack of litigation makes it unclear whether they will properly perform their function. Lacking maturity introduces the risk of appropriation which in turn could reduce incentives to contribute.

%\cite{Weber2004} Weber first tells us what
%open source really is: a radically nontraditional approach to building and distributing
%intellectual property. Rather than protecting, constraining, and charging a fee for the right to
%distribute ideas, open source mandates that the knowledge in question must be openly
%available and widely distributed to the general public, more or less free of charge.

The meaning of open source as a development methodology has been given thorough attention by scholars such as Raymond, von Krogh, von Hippel and Benkler. However, it is important to note that the collaborative practices that are observed in open source development do not require a certified open source license. Several ways of freely revealing innovation outcomes would, at least to some degree, enable others to provided feedback, test and improve that work. These development patterns have been studied extensively and are so closely related to open source development that generalization is justified. Any description that covers more of what goes on in a typical open source community would have to acknowledge that legal tools are only a part of the norms and culture that affect the community's behavior. In that sense, legal tools are just another mechanism that is used because of its good alignment with the practice of collaboration. Other norms, formal or informal and the community's culture also determine to a large degree the behavior of its participants. Norms other than those that are legally binding can be effective at stimulating developers to share their work that builds on shared work. Reciprocity and a shared understanding of fairness can be strong social mechanisms, and these are commonly present in open source communities. The reuse of modules can be encouraged without non-legal norms, moreover even without active encouragement it can still be done without permission. Duplication of effort is still reduced and few transaction costs are involved. 

\subsection{User innovation communities}
A community can be described as a \textsl{``network of interpersonal ties that provide sociability, support, information, a sense of belonging and a social identity''} \citep{FrankeShah2003}. Open source software is typically developed by user innovation communities, but they are by no means restricted to software \citep[p. 103]{VonHippel2006DI_InnoCommunities}. The reasons for participating in a community vary between communities and even between individuals. In user innovation communities, it is typical that intellectual property is not used to prevent others from adopting innovations. The members' willingness to share information usually depends on the functional relationship they have to the object of innovation. If they are interested in benefitting from the use of the innovation, rather than selling it, they are more likely to freely reveal their innovations so that others will improve on their result \citep{VonHippel1988}. These improvements can benefit the initial innovators. Another reason is that it is beneficial for innovators to attract others to their technological trajectory \citep{Osterloh2007}.
Given the tendency towards openness that is common in user innovation communities, there is an obvious good fit with open source licenses.
% In this thesis we consider each open source community an instance of a user innovation community.
% A particularly salient strength of communities is that as they grow larger they can draw on a very large set of resources (connections, hosting, specialist knowledge, willingness to do dull tasks, etc).
% Those communities that encourage these beneficial behaviors are likely to be more successful. For these reason, several governance structures have arisen when needed,

%Nuvolari: Expanding on the work by Dasgupta and David, Foray (2000) has noticed that, in specific historical
%instances, also the production of technological knowledge appears to have been governed by sets
%of “open knowledge institutions”, clearly akin to the ones of “open science”. According to Foray,
%open source software development is one of these cases. Another example put forward by Foray
%in his paper is the case of the Cleveland (UK) iron industry described by Robert Allen (1983).


% OF: ONDER THEORETICAL laten vallen???
\section{Literature review}
There are several research models applicable to open source development that are not limited to software development. We will introduce three of them that appear to be appropriate, briefly compare them and, finally, further review their suitability for the purpose of this research.

%\subsection{Peer production}

%\subsection{Collective invention}
%OS as collective invention is uniquely capable of sustaining knowledge-sharing based on reciprocity even after a dominant design emerges and profit motives enter the picture
%\cite{Osterloh2007}
% . As development shift from exploration to exploitation other cases of collective invention tend to...
%In OS software production, the problem of overuse does not occur since there is no rivalry in consumption. \cite{Osterloh2007}
% Open source software behaves as a public good in the classical sense.
%with information products there is no rivalry in consumption (Baldwin and Clark 2003).

\subsection{User innovation}
User innovation, by definition is an innovation process in which users are the focal actors. As such, networks of user innovators can innovate independently of manufacturers. Such a network can flourish when (1) at least some users have sufficient incentive to innovate, (2) at least some users have an incentive to voluntarily reveal information sufficient to enable others to reproduce their innovations, and (3) user self-production can compete with commercial production and distribution. In case only the first two conditions hold, the innovation process itself still concentrates around users, yet manufacturers focus on their more favorable returns to scale. \citep{VonHippel2007}

% TODO: This is not USER INNOVATION THEORY
Each of these aspects are significantly impacted by the digitization of design and manufacturing processes. Designs become increasingly communicable because of their digital codification. Other than with virtual products, the scaling characteristics of physical production technology determine the fixed costs relative to the variable costs of a product. Computer integrated manufacturing and modular product architectures reduce the trade-off between variety and productivity \citep{Piller2003Variety}. Lower-cost manufacturing tools and services allow a much wider set of people to innovate. The fact that development tools are a significant part of the open source effort itself is consistent with the case of software, and allows commodification of high quality tools (developed mostly by user innovators). This lowers the barriers for people to innovate.

Various researchers have documented the development of physical products by users and user communities. Examples include sports equipment \citep{Luthje2002,FrankeShah2003,Luthje2006,Shah2005}, scientific instruments \citep{VonHippelRiggs1994,VonHippel1976}, medical instruments \citep{Luthje2003} and industrial process equipment \citep{VonHippelSoI1988} and products \citep{VonHippelFinkelStein1979,HerstattvonHippel1992,Nuvolari2004}, Morrison et al. (2002), mass production of steel and the personal computer by \citet{Meyer2003CollectiveInvention}. These communities are by no means restricted to the development of information products like software. They also are active in the development of physical products, and in very similar ways \citep[p. 103]{VonHippelDI2005}.

%"The stickiness of a unit of information is defined as the incremental expenditure required to transfer that unit of information to a specified location in a form usable by a specified information seeker"﻿\cite{VonHippelStickyInfo1994}. 

%"Open source: it can optimally profit from the developments of other firms that build on its own efforts, since it induced others to invest their efforts in areas where it has a high absorptive capacity."Osterloh M, Rota S. Open source software development - Just another case of collective invention? Research Policy. 2007;36(2):157-171. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0048733306001983. .

\section{Motivations to participate}
% Show how this is the case!? Refer to the quantitative study!


% 

\subsection{Autonomy}
It is common in open source communities that members have no formal authority over each other in the community. \citet{DahlanderLateralAuth2008} argue that progression can be achieved in project-based organizations that reward people with greater authority over collective work even though they do not gain authority over other individuals. In other words, the members are autonomous in that they can themselves decide what they want to work on. 
% self-directed / Self-determination theory (SDT) by Deci and Ryan cite autonomy as one of three basic human needs.
% scientists have found that autonomy is something that people seek and that
Consequently, they will in general not work on aspects that they do not enjoy working on. This enjoyment can be rooted in pleasure from learning something new and gaining competence, or a sense of fulfillment from being able to utilize their talent to solve challenging problems.

% Most members of the community are not paid or formally rewarded for their participation in the project. 
Research suggests that this might actually be beneficial for sustaining creativity and innovation. \citet[p. 79]{AmabileKillingCreativity1998} states that extrinsic motivation is to be seen mostly as a potential source of creativity problems. In the same paper she suggests that intrinsic motivation is a key determinant for creativity.

A meta-analysis of several psychological studies by \cite{DeciExtrRwrdsUndrmineIntrMotiv2001} shows that extrinsic rewards can crowd out intrinsic motivations. Because of the dominance of activities that are enjoyed and the absence of external stimuli, most members can be considered to be intrinsically motivated. When a person is intrinsically motivated, he or she enjoys the process over specific results. Amabile calls this the Intrinsic Motivation Principle of Creativity: people will be most creative when they feel motivated primarily by the interest, satisfaction, and challenge of the work itself, and not by external pressures \cite[p. 79]{AmabileKillingCreativity1998}. Because of this, creative, explorative behavior can be expected to be more salient.

%In open source software a considerable fraction of the people are paid while working on open source software. 

% Psychological needs and the facilitation of integrative processes. Journal of Personality. 63. pp. 397-427

% Amabile creativity intrinsic motivation
% Everyone who works in the RepRap project mostly manages his or her own budgets, because it usually is their own money that they are spending, in contrast to organizational spending. For example, use of a company resource such an money may require approval in advance. Spending it unwisely in the eyes of your colleagues or superiors might be a source of tension or even conflict. By contrast, in the RepRap community there is no need to convince people of the value of a costly experiment for the sake of approval. This means that even if an approach may not seem like a viable alternative to most people in the community, it can and will still be tried as long as at least one person is motivated do so. 

% Valery Chir
% The autonomy is not to be mistaken for independence. The people that work on the RepRap have a good sense of the value that other have brought to the table and that they could never have done all of the work by themselves. Also, most people acknowledge that the social component that is present in the community is important to them.

The positive and rewarding properties that a individual attributes to the participation in the project are beneficial to the project because it is responsible for attracting new participants. In addition, the participants who are attracted are not only highly motivated, but also creative and can autonomously decide to experiment and innovate as much as they like.

With the completion of their RepRap 3D printer a person acquires both a powerful tool and the skills to create new physical objects. The people in the RepRap community tend to be inclined to work creatively on challenging problems. Apart from improvements related to the machine itself, a lot of additional innovations are likely to be created. For some people, being able to work on other, non-RepRap related innovations may be an important reason to build such a machine.

\subsection{Striving for competence}
Studies have shown that it is common in open source software projects that enjoyment-based intrinsic motivation is the strongest and most pervasive driver \citep{LakhaniFlossMotivation2005}. Also, intellectual stimulation and gaining competence are provided as top motivators for participation. The observation that open source projects often attract new participants based on their intellectual challenging aspects is explained by psychologists as a natural inclination. \citet{RyanDeciSDT2000} state that \textsl{``the construct of intrinsic motivation describes this natural inclination toward assimilation, mastery, spontaneous interest, and exploration that is so essential to cognitive and social development and that represents a principal source of enjoyment and vitality throughout life''}.

\citet{LakhaniFlossMotivation2005} also note that in their sample of open source projects, a participants' high rating of the creativity of their involvement was the strongest determinant of the number of hours that were weekly spent in the project. The multi-project sample revealed that the sense of creativity is endogenous to the people within the projects, and not just a property of the project.
%en hoe zit dat in onze sample?
% ``Intellectual, manual, and creative stimulation. All of which are sorely lacking in day job.''

% Effects of user innovation by amateurs
There are important implications if a community constitutes of a set of people who are primarily motivated by the desire to learn. It means that there are community members that innovate outside of their normal area of profession. They see it as a learning opportunity in addition to various other motives. The important difference is that they were not assigned to perform a certain task, they self-selected it. Amateurism may increase the chance of discovery of unintended beneficial effects ex post. Because the amateur selects the activity, frequently because he enjoys performing it, his/her mind is not clouded by specific goals that were set by others. In the case of expert, assumptions and readily available solution dominant knowledge leads to a more constrained exploration of the solutions. Being familiar with previously established 'best practice' solutions can make it harder to envision or discover alternative solutions that may be more appropriate.
The exploratory attitude of users that self-select the problem they want to work on are motivated to gather solution knowledge. In other words, since he/or she is a user, he knows which problem to solve and is motivated to acquire the new knowledge if it he doesn't possess it already. Understanding which problem to solve, understanding the context of use is an example of sticky information \citep{VonHippelStickyInfo1994}.


\subsection{Meaning}
% The work done in the RepRap community is by its members generally perceived to be meaningful. Moreover, building a RepRap and improving it is a process of gaining competence. 

\citet{ArielySearchForMeaning2008} have found important differences in motivation between work that was perceived as meaningful and work that seemed meaningless. 
%As we will find in chapter ...
%In the survey, participants frequently stated reasons such as ``to participate in the future'', ``because I think RepRap will be extremely important''. Others mentioned it was to make sure everyone can have a personal factory at home.

% The meaning that the project has for these people makes them highly motivated.





%\section{Findings}

\chapter{Case study}\label{Ch:CaseStudy}
One of the more ambitious open design projects is the RepRap project. Its goal is to collaboratively develop a low-cost fabrication device that can to a large extent produce a physical copy of itself. The RepRap machine is often described as a 3D printer, one that creates strong, tangible objects of arbitrary shape. Based on digital design files that are openly shared, the machine can be used to fabricate physical objects of value to the user. Users share and use design files of physical objects. One of these collaboratively developed designs is the RepRap machine itself. Users of RepRaps have the tools to fabricate modification for the machine that they operate.

This chapter starts by looking into this user innovation process by seeing who is innovating and how they are motivated. 
% Next, ...


\section{The RepRap Community: an introduction}
This chapter starts with how the project was initiated. We will identify properties that enable the form of collaboration that is observed in the RepRap project, which a result of the replication aspect and the fact it materializes digital input.
You cannot fully understand an instance of innovation or collaborative processes unless you know who is doing it. The survey in chapter \ref{Ch:Survey} will go into much more detail on the participant's motivations, functional relationship to the invention and innovation assets.
% LOOPT NIET LEKKER!
Here we will show how work is coordinated. Project governance and the technical infrastructure play an important role. I will describe how the architecture can affect coordination.
%[Fact that it's done is proof]
%[Does this fully answer: Who is doing it? Why? How?]


\section{RepRap as an open source community}
% Heterogeneity and problem solving, relate this to the paper: The Impact of Team Familiarity and Variation in Experience

%\section{Findings}

%From Nuvolari: Motivations: enhancing their future career perspectives. Raymond also notices that “Occasionally the reputation one gains in the hacker culture can spill over into the real world in economically significant ways”, however, in his view, this is rather sporadic so it would be wrong to regard it as the main motivational drive (Raymond (1999), p.97). This drive seems to be present at least to some extent, as several of the respondents have referred to ``World domination'' as one of their reasons to participate in the project.


In 2004 Adrian Bowyer, a professor at the University of Bath, proposed the idea of creating a rapid prototyping machine that could make a significant fraction of its own parts. His goal was to make this technology accessible to anyone who wanted it. Bowyer mentions three important qualities of his envisioned machine were (1) that the number of them and the wealth they create could grow exponentially, (2) the machine becomes subject to evolution by artificial selection and (3) that it creates wealth with minimal dependence on industrial manufacturing\footnote{From http://www.bath.ac.uk/~ensab/rapid-prototyping/ retrieved 3 January 2005, via The Web Archive}.

Rapid Prototyping machines have existed for over 20 years, but never at a price point attractive for domestic and hobbyist use
% [TBD: ref]
. The so called Additive Manufacturing (AM) industry is introducing lower-costs AM machines, but so far most of them are above 10,000 euros. The RepRap is designed to be built for less than 500 euros, which has allowed a wider set of people to experiment with the technology and improve it.

\section{Unique characteristics and adoption}
For diffusion of the invention to occur, those adopting it have to have reasons to have such a machine and the means to obtain it. Most of the practical reasons for adopting the machine result from its wide range of applications, low switching cost of between different production jobs and the benefits of using digital designs as input. Within the build volume of the machine, there are few restrictions on the shape of the object that it fabricates. This is relatively unique and is a result of layer based technology used. Moreover, the specific object that it fabricates depends on the digital design file that is selected. Very significant is the ease with which designs can be distributed, since a large fraction of the design and fabrication information is codified into the digital file. A resulting attractive feature is that physical upgrades and variations can be fabricated with the machine, and that these variations can be shared digitally with relative ease. This enables the artificial selection (ad 2), carried out by relatively independent individuals and organizations (ad 3).

\section{Evolution and governance}
After Dr. Bowyer's initial proposal to build a RepRap in 2004, experiments at Bath University were conducted of which the results were shared online. This captured the interest of a widely distributed audience who joined the experimentation and pooled their knowledge. In the first year, less than 10 people were involved. Most notably, Vik Oliver, an open source enthusiast from New Zealand developed and built several of the early prototype machines\footnote{Oliver, V. Construction of Rapid Prototyping Testbeds Using Meccano. May 2005}. Zach Smith, a web-developer based in New York City, designed circuit boards and started selling kits through a foundation that he set up in conjunction with the core team.

\label{governance}
Within the RepRap community, you can distinguish between the core and peripheral community (with regards to level of involvement). When more people volunteered, a core team was assembled which included most of the people who were involved early on. Over time, more people from the community were included in the core team. They are voted on board by unanimous vote. The core team can be considered a non-hierarchical group. 
% Note that this is consistent with the literature.... (footnote, shouldn't distract)
% Check if duplicate: \citet{DahlanderLateralAuth2008} argue that progression can be achieved in project-based organizations that reward people with greater authority over collective work even though they do not gain authority over other individuals. 
New core members are invited based on their merit. If you engage more heavily in problem solving in the community, you're more likely to progress to the center. Moreover, the core members take some level of responsibility of coordinating work, yet for many issues the whole community is consulted. Historically, the core team has taken decisions regarding the architecture of designs and infrastructure for collaboration.
Because there is no formal authority over persons, everyone in the community is free to disagree with decisions and implement things in a different way. This way they can prove the value of a different approach. Most individual innovators are in control of their own budgets and decide themselves what to spend their time on.

\section{Technological innovations}
Adopters of RepRap technology have an valuable set of prototyping tools at their disposal that also allows them to improve the technology itself. Moreover, those benefiting from its use will have an incentive to improving it. Improvements can include added functionality, improved existing functionality, increased ease of assembly and use, lower-cost, more suitable (e.g. easier-to-acquire) components, specialization towards a certain application, extending auxiliary tools, interoperability with other systems, improved design architecture and developing or refining operating techniques. In addition, several layers of the stack of technologies used can be discerned. These include, physical/mechanical, electromechanical, microcontroller firmware, etc. See appendix \ref{apdx:innovationList} for a list of innovations in each of these categories.

A sustainable innovation process relies on radical and incremental innovations. In other words, the viability of communal development of designs of physical objects relies on the ability to generate both types of innovation.


The diversity of community members, with respect to motivations and innovation assets held, may reflect on the aspects being given attention. User innovators are found to create innovations with more functional novelty\footnote{See \cite{VonHippelRiggs1994}, “Incentives to innovate and the sources of innovation: The case of scientific instruments,” for an analysis showing how novel functionality emerges from users.}.
%% TABLE WITH INNOVATIONS?

\section{Distribution and diffusion of innovations}
%[We're not talking about ordinary diffusion of innovations from manufacturer to consumer, but among innovators and between innovators and early adopters]

% TBD: (ref. to Rogers) 
Depending on the architecture and level of modularization, a change in a digital design can be made and communicated at a certain cost. The cost of making changes depends on the tools used, their interoperability with the information-structures used. The cost of communicating the design change depend on the sender and recipient. Codification and stickiness of information are important issues. The cost of integrating this change.
Several motives for free revealing of improvements. Compliance with formal/informal communal norms and licenses. Both users and manufacturers can benefit from others investing in developments that build on theirs, since they have a high absorptive capacity in these areas \citep{Osterloh2007}. 
% this is THEORY

If designed objects can be automatically fabricated, this has important consequences. Whereas physical objects take up space and can only be in one place at the same time, storage and distribution of design information is greatly facilitated by our digital communications infrastructures. The means to obtain it are facilitated by the partial replication capability. Additionally, the choice for an open source license (the GNU General Public License) was made to ensure inclusive access to the design files and to encourage collaboration.
Since the inception of the project, several thousands of people have built RepRap or derivative machines. Some project participants have started businesses in selling parts and kits. As the project advances, more people are capable of printing out the machine parts for which there is a large demand. Some individuals RepRap members have reported to have printed more than a dozen sets of parts for others.

% or: motivation
\section{Motivations to participate}

In interviews with many members of the RepRap community three basic motivations seemed to be responsible for people to choose to participate in the project. Autonomy, the desire for competence and purpose appear to be important motivators.
% Show how this is the case!? Refer to the quantitative study!


% 

\subsection{Autonomy}
As mentioned in section \ref{governance} about governance, and like in any open source community, there is no formal authority over members in the community. The members are autonomous in that they can themselves decide what they want to work on. 
% self-directed / Self-determination theory (SDT) by Deci and Ryan cite autonomy as one of three basic human needs.
% scientists have found that autonomy is something that people seek and that
Consequently, they will in general not work on aspects that they do not enjoy working on. This enjoyment can be rooted in pleasure from learning something new and gaining competence, or a sense of fulfillment from being able to utilize their talent to solve challenging problems.

Most members of the community are not paid or formally rewarded for their participation in the project. Research suggests that this might actually be beneficial for sustaining creativity and innovation. \citet[p. 79]{AmabileKillingCreativity1998} states that extrinsic motivation is to be seen mostly as a potential source of creativity problems. In the same paper she suggests that intrinsic motivation is a key determinant for creativity.

A meta-analysis of several psychological studies by \cite{DeciExtrRwrdsUndrmineIntrMotiv2001} shows that extrinsic rewards can crowd out intrinsic motivations. Because of the dominance of activities that are enjoyed and the absence of external stimuli, most members can be considered to be intrinsically motivated. When a person is intrinsically motivated, he or she enjoys the process over specific results. Amabile calls this the Intrinsic Motivation Principle of Creativity: people will be most creative when they feel motivated primarily by the interest, satisfaction, and challenge of the work itself, and not by external pressures \cite[p. 79]{AmabileKillingCreativity1998}. Because of this, creative, explorative behavior can be expected to be more salient.

%In open source software a considerable fraction of the people are paid while working on open source software. 

% Psychological needs and the facilitation of integrative processes. Journal of Personality. 63. pp. 397-427

% Amabile creativity intrinsic motivation
Everyone who works in the RepRap project mostly manages his or her own budgets, because it usually is their own money that they are spending, in contrast to organizational spending. For example, use of a company resource such an money may require approval in advance. Spending it unwisely in the eyes of your colleagues or superiors might be a source of tension or even conflict. By contrast, in the RepRap community there is no need to convince people of the value of a costly experiment for the sake of approval. This means that even if an approach may not seem like a viable alternative to most people in the community, it can and will still be tried as long as at least one person is motivated do so. 

% Valery Chir
The autonomy is not to be mistaken for independence. The people that work on the RepRap have a good sense of the value that other have brought to the table and that they could never have done all of the work by themselves. Also, most people acknowledge that the social component that is present in the community is important to them.

The positive and rewarding properties that a individual attributes to the participation in the project are beneficial to the project because it is responsible for attracting new participants. In addition, the participants who are attracted are not only highly motivated, but also creative and can autonomously decide to experiment and innovate as much as they like.

With the completion of their RepRap 3D printer a person acquires both a powerful tool and the skills to create new physical objects. The people in the RepRap community tend to be inclined to work creatively on challenging problems. Apart from improvements related to the machine itself, a lot of additional innovations are likely to be created. For some people, being able to work on other, non-RepRap related innovations may be an important reason to build such a machine.

\subsection{Striving for competence}
% Ref to Theory: Studies have shown that it is common in open source software projects that enjoyment-based intrinsic motivation is the strongest and most pervasive driver \citep{LakhaniFlossMotivation2005}. Also, intellectual stimulation and gaining competence are provided as top motivators for participation. The observation that open source projects often attract new participants based on their intellectual challenging aspects is explained by psychologists as a natural inclination. \citet{RyanDeciSDT2000} state that \textsl{``the construct of intrinsic motivation describes this natural inclination toward assimilation, mastery, spontaneous interest, and exploration that is so essential to cognitive and social development and that represents a principal source of enjoyment and vitality throughout life''}.

% \citet{LakhaniFlossMotivation2005} also note that in their sample of open source projects, a participants' high rating of the creativity of their involvement was the strongest determinant of the number of hours that were weekly spent in the project. The multi-project sample revealed that the sense of creativity is endogenous to the people within the projects, and not just a property of the project.
%en hoe zit dat in onze sample?
% ``Intellectual, manual, and creative stimulation. All of which are sorely lacking in day job.''

% Effects of user innovation by amateurs
% There are important implications if a community constitutes of a set of people who are primarily motivated by the desire to learn. It means that there are community members that innovate outside of their normal area of profession. They see it as a learning opportunity in addition to various other motives. The important difference is that they were not assigned to perform a certain task, they self-selected it. Amateurism may increase the chance of discovery of unintended beneficial effects ex post. Because the amateur selects the activity, frequently because he enjoys performing it, his/her mind is not clouded by specific goals that were set by others. In the case of expert, assumptions and readily available solution dominant knowledge leads to a more constrained exploration of the solutions. Being familiar with previously established 'best practice' solutions can make it harder to envision or discover alternative solutions that may be more appropriate.
% The exploratory attitude of users that self-select the problem they want to work on are motivated to gather solution knowledge. In other words, since he/or she is a user, he knows which problem to solve and is motivated to acquire the new knowledge if it he doesn't possess it already. Understanding which problem to solve, understanding the context of use is an example of sticky information \citep{VonHippelStickyInfo1994}.

\citep{Kristensson2004HarnessCreativeUserPot} note that "[t]he results indicated that ordinary users create significantly more original and valuable ideas than professional developers and advanced users. Professional developers and advanced users created more easily realizable ideas, and ordinary users created the most valuable ideas. The results were discussed from the viewpoint of divergent thinking. It was suggested that divergent thinking was facilitated through the opportunity to combine different information elements that appeared separate at the outset, such as personal needs coupled with the functionality of mobile phone services." 
The cognitive distance within a group of engineers with similar education is much smaller than a loosely connected group of individuals who work in different parts of the world and have very different backgrounds and resources at their disposal. These kinds of discoveries are more likely to occur when amateurs try various solutions even if there are best practices that are otherwise relied on.


\subsection{Meaning}
The work done in the RepRap community is by its members generally perceived to be meaningful. Moreover, building a RepRap and improving it is a process of gaining competence. 

\citet{ArielySearchForMeaning2008} have found important differences in motivation between work that was perceived as meaningful and work that seemed meaningless. In the survey, participants frequently stated reasons such as ``to participate in the future'', ``because I think RepRap will be extremely important''. Others mentioned it was to make sure everyone can have a personal factory at home.

The meaning that the project has for these people makes them highly motivated.
% TODO: see if there's a pattern between 'high meaning` and effort.
% In the survey, from 50 random responses 9 specifically took the time to further elaborate on why they are motivated to participate in the project. They following 9 quotes were selected to give an impression of how meaningful the project can be to people in the project:
% 
% ``Participating in the future''\\
% ``not that difference from the personal computer revolution''\\
% ``participate in one of the most exciting open source projects that exist and be part of something that will have a huge impact on manufacturing goods, the world, economy etc.''\\
% ``because a new revolution is upcoming!''\\
% ``I love the potential of the Reprap, and want to help develop it to the point where home 3d printers become widespread.''\\
% ``Hope to change the world by democratizing design and manufacture of material goods.  good for freedom, good for planet.''\\
% ``I want to be part of something like the reprap that I think will be extremely important (like having an apple II in the late 70's)''\\
% ``Every home need a replicator''\\
% ``The thought of helping to make 3D printing far more accessable to most households and third world countries in the hopefully not-too-distant future.''\\



%Falk and Kosfeld (2006): close supervision of workers might undermine intrinsic motivation. 
%"When money is used as an external reward for some activity, the subjects lose intrinsic interest for the activity." Edward L. Deci, "Effects of Externally Mediated Rewards on Intrinsic Motivation", Journal of Personality and Social Psychology 18 (1971): 114.

% 

\section{Case analysis} %Was 2.8 Findings
The case study explores the operation of the open source development process in the RepRap and directly related communities. Many of the community members possess a relatively unique fabrication capability. Special attention is given to the role of this capability and its effect on collaboration. It affects the cost of development, production, reproduction and distribution of physically embodied innovations. Due to artifact embodied tacit knowledge it affects the locus of innovation.    Practically it affects the fraction of the project's modules that can be developed through the open source development process, such as the dependence on external parties for manufacturing off-the-shelf components. It also has implications for the architecture and incentives (you can scratch your own itch). 
In particular, the diffusion of innovations with artifact-embodied information is first addressed theoretically, identified in the case study and tested quantitatively through the survey.

While these are currently unique capabilities, this doesn't mean that this necessarily remains the same for long. The fact that the technology is rapidly becoming more affordable, able to produce higher quality objects, that libraries of designs already exist and have rapidly increasing growth rates indicates that widespread adoption is not just plausible but almost inevitable. Therefor, as new cohorts adopt the technology they will increasingly demand further maturization of technologies.


% MOTIVATION %
Industrial product development and engineering are generally regarded as activities that require payments and career incentives to induce effort. When compared to adopting a piece of software, acquiring and assembling a RepRap-kit entails considerable effort and even money. 
% The effort and expenditure is justified by ...

Within the RepRap project extrinsic motivation such as payment is a modest/negative predictor of effort.
The primary motivations within the RepRap community are consistent with the most important motivation that were identified in studies of open source software communities. The community appears to consist of highly motivated, creative and innovative individuals.
Considerable effort is invested in the project while the results are made available to anyone.

% TODO: Bradshaw2010

\section{Conclusions}
% New section proposed by O'Callaghan
% TODO

\chapter{Survey}\label{Ch:Survey}
Empirical data was gathered by administering a survey to those who build and/or operate open source 3D printers. The final survey was administered via the web. It was available at ``http://www.reprapsurvey.org'' from 25 February to 18 March 2010. Please see appendix \ref{apdx:survey} for a copy of the full survey. At that time the total community is roughly estimated to have between 2000 and 3000 members, based on sales data of various kit builders and estimates provided by members of the core team. The survey is quite extensive (up to 72 questions when applicable) and on average took between 13 minutes and 28 seconds to complete. 386 complete responses were received.\\
\\
The survey was divided in the following sections:\\
\\
% \begin{verse}
A. Type of user\\
B. Adopting the machine\\
C. Innovating the software\\
D. Innovating the hardware\\
E. Thingiverse\\
F. Demography and general questions
% \end{verse}

The survey tracks the entire process from adoption of the platform, to development of innovations and, where applicable, their free revealing and their diffusion.

Section A and B contain questions regarding the adoption of existing technologies. Problem incidence and problem-solving is measured, Specific attention is paid to whether the user has a local support group or not. 
In section C and D we track newly created innovations from creation, free reveaing and diffusion to others. 
Thingiverse.com is a website to share digital designs for physical objects. The majority of the users of this website is affiliated with the RepRap project and many of them have their own fabrication devices. In section E on Thingiverse, we focus on the community based prototyping of new objects and the fully distributed manufacturing.

\section{Overview of the results}
\subsection{Community growth}
One of the first remarkable findings derived from the survey is the growth characteristics of the community. As shown in figure \ref{fig:adoption}, most of the people who get involved the project and that adopt the technology have done so fairly recently. The adoption rate increases so fast that new adopters outnumber all previous adopters that had joined more than 6 months ago. Since a significant proportion of the whole community is sampled (estimated between 10 to 20\%), it is probably representative. It also hold another powerful message. An attempt to measure the size of the community is prone to be outdated when analysis of the collected data is completed. Yet, especially in the long run, the precise size is far less important than its growth rate.
What this figure also shows is that the community can attract new participants. Obviously this type of growth creates the challenge to integrate the efforts of a growing amount of individuals.

% PUT THIS AS CLOSE AS POSSIBLE TO THE REFERENCE.


Because of the rapid exponential growth, a logarithmic scale is more included (figure \ref{fig:adoptionLog}). 

Regression-fitting this growth curve yields a duplication of the community every 6.03 months and a 10 fold growth every 20 months\footnote{Using a non-linear least squares fit (Levenberg-Marquardt nonlinear regression).}. If this growth rate would continue unabated this means that there would be 10 million operators by 2016 and over 1 billion operators in the course of 2019. Obviously, extrapolating this far out of the data assumes that there are no fundamental changes to growth characteristics.

Not only do RepRaps spread to more individuals, the individual operators of working machines have the capability to make more of them. The respondents were invited to list the machines they had. 52\% of the people have at least one working machine. The average operator has 1.52 machines (working or being constructed). More than half of the respondents had multiple distinct types of machines (table \ref{table:machineTypes}). They possibly have several instances of each distinct type of machine they own.
\begin{table}[b!]
\caption{\textbf{Distinct number of machines per operator}}
\begin{center}
\begin{tabular}{cc}
\hline
No. of distinct \\
types of machines		& Frequency \\ 
\hline
1 		& 237 
% TODO: (add percentages!( \%)
 \\
2 		& 108 \\
3 		& 28 \\
4 		& 9 \\
5 		& 2 \\
\hline
\end{tabular}
\end{center}
\label{table:machineTypes}
\end{table}

\begin{figure}[H]
\subfigure[\textbf{The cumulative amount of sampled operators involved.}]{

 \includegraphics[bb=0 0 472 378,width=120mm]{AdoptionLin2.pdf}
 \label{fig:adoptionLin}
}
\subfigure[\textbf{Depicted on a 10-log scale.}]{
 \includegraphics[bb=0 0 475 382,width=120mm]{AdoptionLog2.pdf}
 \label{fig:adoptionLog}
}
\caption{The cumulative amount of sampled operators involved. \\
\textasteriskcentered~ Note that the actual number of operators is higher, depending on the ratio between population and sample size. This ratio is roughly estimated to be 5:1 or higher.}
 \label{fig:adoption}
\end{figure}





It is common not to make another copy of the same machine if a later version can be adopted. 
% TODO: Refer to appendix with correlation matrix?
While there are some substitution effects, some more commonly taken upgrade paths can be identified. So called "bootstrap machines" can be constructed from ubiquitous parts available in hardware stores, or kits are available from various suppliers. These machines can be used to make the parts for a RepRap, that can in fact make its own parts.

Because most RepRap models are not finished products that are bought but rather parts that one acquires from one or more sources, many people are in the stage of building a machine. The proportion that is still building a machine is higher because of the high ratio of recent adopters, as seen in figure \ref{fig:adoption}.

%\section{Motivations}
%TODO

\subsection{Innovating the software versus hardware}
The level of innovation in either software or hardware depends on several variables. These variables include: (1) inherent properties of respectively the immaterial and material product (2) the result of the availability and quality of development tools. (3) the skills and resources available to the innovator, such as time, money, knowledge, equipment, reusable modules, etc. (4) the incentives, perceptions and motivation of the innovators. (5) the ability to collaborate and integrate work and the scalability of such collaborations.
% THIS SHOULD BE JUSTIFIED!


%Introduce the Table ... 
% split first line -> different logic. Percentage, instances, total sample size


Interestingly, more people actually modified and/or developed physical components (hardware) than they did with software (a in table \ref{tab:HWSWinno}). To some extent, the fact that you can develop hardware in this project might be an attractive feature of the project, leading to hardware developers being overrepresented.
It also could have to do with problems in the hardware, which has to be physically implemented anyway can be resolved by modifications or by taking another approach. 
% For example, if replicating someone else's physical setup costs a fixed amount if time, and using a different approach takes only slightly more time because you can use a different technique, this might seem appealing. 
Perhaps it is more transparent how a certain hardware problem can be resolved than it is for a software problem.

% [Are modification more radical? Are they done for different reasons? Are different sources consulted? Was there more or less collaboration? More local collaboration? More or less time involved? (more different task granularity?)]

If there is no diffusion, a modification is just a local invention with limited impact. A modified software or hardware setup is not necessarily completely revealed to everyone in the format best suitable for modification by others. This may happen in a smaller circles, such as within (geographically concentrated) subgroups. The innovation may be shared incompletely, e.g. a photo is shared but not the design files or design files are shared but not documented. This in turn limits the level of collaboration that is possible. However, it is not uncommon for innovation to be detailed extensively in blog posts and/or wiki pages. 
One would expect a higher geographic concentration when collaborations deal with a hardware modification. While this may be the case, it did not limit the level of collaboration severely, as there is more collaboration in the hardware than sofware (b in table \ref{tab:HWSWinno}). This can only partly be explained by the level of free revealing being higher in hardware (121, or 64\%) than in software (62, or 61\%).
% TODO: [include data on sharing with local group only]

An individual's motivation and perception of difficulty can determine what innovations will be be developed. This depends to a large extent on the personality of an individual and the structure of the incentives. If the incentives have to do mostly with learning, a difficult task might be undertaken instead of an easy one. On the other hand, difficult tasks, or tasks where skills may be limited may be avoided by others. Rather than trying to fully understand the complex interactions of these hard to measure properties, we let people judge to what extent people had adopted their innovations and what difficulties they would encounter. With hardware, there were less difficulties anticipated (c in table \ref{tab:HWSWinno}).

% table is not introduced before it is displayed.
\begin{center}
\begin{table}[]
\caption{Software versus hardware innovation in the RepRap community}
\label{tab:HWSWinno}
\begin{tabular}{lrrrcrrrc}
\hline\\ 
  & \multicolumn{3}{c}{\textsl{Software}}& & \multicolumn{3}{c}{\textsl{Hardware}} \\
\cline{2-4} \cline{6-8}\\
& & \textsl{inno-} & of & & & \textsl{inno-} & of\\
& \% & \textsl{vations} & \textsl{total} & & \% & \textsl{vations} & \textsl{total}\\
\hline% \cline{2-4} \cline{6-8}\\
% \hline 
% Level of innovation\textsuperscript{a} &		101 & 26\% &&	189 & 49\% && 384\\
\\
Types of innovation \\
~~~ New functionality &		50\% & 50 & 101 & & 	37\% & 69 & 189\\
~~~ Convenience &		76\% & 77 & 101 & & 	65\% & 123 & 189\\
~~~ Performance &		41\% & 41 & 101 & & 	53\% & 100 & 189\\
~~~ Novelty &			33\% & 33 & 101 & & 	22\% & 42 & 189\\
Level of collaboration\textsuperscript{b} & 
				26\% & 26 & 101 & & 	33\% & 62  & 189\\
Free revealing & 		61\% & 62 & 101 & & 	64\% &121 & 189\\
~~~ No exclusion &		73\% & 45 & 62 & & 	81\% & 98 & 121\\
Diffusion of innovations \\
~~~ Expected diffusion & 	30\% & 30 & 101 & & 	22\% &42& 189\\
~~~ Local diffusion only & 	0\% & 0 & 12 & &	18\% & 3& 17\\
~~~ Ease of adoption\textsuperscript{c} & 
			      11\% & 11 & 101 & & 	26\% & 49 & 189\\
Adoption blockers \\
~~~ Too specific to user need & 40\% & 40 & 101 & & 	16\% & 30 & 189\\
~~~ Too experimental & 		56\% & 57 & 101 & & 	47\% & 88 & 189\\
~~~ Benefits not apparent & 	3\% & 3 & 101 & & 	9\% & 17 & 189\\
~~~ Long time to implement & 	5\% & 5 & 101 & & 	13\% & 24 & 189\\
~~~ Sticky information & 	5\% & 5 & 101 & & 	4\% & 7 & 189\\
~~~ Expensive & 		1\% & 1 & 101 & & 	3\% & 6 & 189\\
~~~ Difficult to integrate & 	7\% & 7 & 101 & & 	6\% & 11 & 189\\
\\\hline \\
% \multicolumn{4}{l}{test\\test}
% \multicolumn{6}{l}{Notes: \textsuperscript{a} Significantly more innovations are developed for hardware than for software.}
\end{tabular}
% \textsuperscript{a}The total number of hardware innovations is higher than for software.\\
\textsuperscript{b}There is more collaboration in hardware than in software.\\
\textsuperscript{c}The developed hardware innovations are perceived as easier to adopt by others.\\
\end{table}
\end{center}
% In table \ref{tab:HWSWinno}
\section{Conclusions}
% Voorgesteld door R'OC.
% Conclusions on: Adoption and diffusion, hardware vs. software. Implications for research.

%TODO: Alles hierboven tot Innovating the software versus hardware






\chapter{Confronting theory with practice}\label{Ch:Theory2Practice}
Clearly, the prevalence of open modes of production depends on access to the required tools and informational resources and incentives to participate. As it usually is a product of the interactions between many individuals, the cost and incentive structures are essential to understanding individual and group behaviors in such communities. The open source physical production of goods is facilitated by three major factors. 
% Firstly, lower costs encourage more innovation. This cost is lowered by the the increasing digitization of the design process, which allows developers to incur less material costs. 
Firstly, an individual participant's low fixed and incremental costs to design and physical production and integration of that which is produced. Secondly, incentives that justifies the incurring said costs, if applicable. Thirdly, open collaboration as a means to spread the workload and have access to the much larger collective assets that help achieve the individual goals. In this chapter we will go over each of these factors, as they relate to software production and production of physical objects.
% where do these come from?! 
% TODO: THIS SHOULD BE JUSTIFIED. REFERENCES!!!!! 3 at LEAST....
\section{The costs of the tools of production and distribution}

The tools required for software production are widely available and cheap, as pointed out, among others, by \citet[p. 106]{LakhaniPanetta2007PrinciplesOfDI}. This is consistent with the observation that a lot of development tools have been created by open source communities, often because it helped the participants in their daily work. Of the more than 230,000 projects listed on SourceForge, a popular site where open source projects can be hosted, 34,000 fall in the category "Software development". It contains many examples of tools that are of high quality and that gained significant prominence even in the presence of the large commercial and initially proprietary market. Moreover, all of the open source tools can, by definition, be distributed at no charge. Clearly, the availability of affordable, high quality development tools helps lower the barriers to production of software.

After initiation of a project, collaborative production requires replication of the current state of a project and distributing the locally made changes back to the project's source code repository. Distribution and testing of the whole software product can be done at a close-to-zero costs and no third party needs to be involved to fix a bug~\citep[Ibid., ][p. 22]{VonHippelKrogh2006}. The private transaction costs can be low enough to justify the private benefits derived (a better product). Sharing the modification for the public benefit of others often involves minimal effort and often has some private benefits.

The design process for physical objects is increasingly digitized, thanks to increasingly powerful and affordable computer aided design (CAD) software. This results in further codification of designs and low transaction costs for replicating the results and sharing the workload. A web page with some CAD-files and instructions can suffice to enable others to replicate a result and build on it.

Potential users of an innovation collectively already hold a major knowledge assets that are required to create the innovations, because of their access to need-related and context-of-use information~\citep{Shah2005OpenBeyondSoft}. Another major component is solution information, which can be acquired through trial-and-error experimentation and which can be shared in a community (proved viable by Wikipedia). As a result, in many cases this means that together they can innovate at a lower cost. However this requires access to prototyping tools and resources and the ability to distribute private prototyping costs among participants so that they are more than offset by the individual participants' benefits.


\subsection{Prototyping cost drivers}\label{protocosts}
Prototyping 'virtually' usually doesn't involve a large monetary investment. To understand the barriers to distributed prototyping and the extent to which it may be feasible, it is of crucial importance to understand the cost-structure of physical prototyping. Physical prototyping requires an investment in physical resources, some of which are fixed costs, others incremental, such as costs per design iteration.
% * benefits of being able to save of expensive resources (e.g. rapid prototyping technology costs are mostly saved). Ways to reuse a power drill for making a lath and later 3D printing a lathe, etc.
Resources that are occasionally needed and that have a long life-time are candidates for sharing, examples are workspaces, power tools and digital fabrication equipment.
% ** Social systems with a a high degree of trust have lower transaction costs (e.g. local communities that trade and share and know each other personally, RR). This could be another innovation edge over firm-based production. The importance of local communities is part of the survey!
Materials may be used once per iteration or reused\footnote{It is perhaps of interest to note that full recycling of parts and even automated assembly and disassembly are the holy grails of physical prototyping and people within the RepRap community are working towards these goals.}. To the extent to which customized parts cannot be recovered or recycled for further prototyping iterations these are unavoidable costs. But the amount of unrecoverable parts can be reduced through design architecture and a distributed search for ubiquitous low-cost parts. Assembly time is often at odds with modularization, so in some cases the use of unrecoverable custom parts can be a deliberate choice in order to reduce assembly time, which is another major input to prototyping costs. Computer driven production technologies and especially 3D printing are well suited for part consolidation. Very complex multi-part objects such as a clock with gears and a pendulum can be 3D printed in one go without requiring any human assembly or intervention.

The cost of a 3D printed prototype used to be much higher than it is now. There are two ways to obtain a 3D printed prototype: through in-house rapid prototyping and through prototyping service bureaus. Having access to a RepRap significantly lowers the cost of physical prototypes when compared to the prints from models available from commercial vendors. It is not uncommon for people with RepRaps producing objects based on ideas that's friends provided, since the costs involved are relatively modest. This has to do with a large difference in price of both the machines and the consumables (e.g. production thermoplastics). The RepRap and most of its derivatives are sub-1000 dollar 3D printers while most commercial vendors offer such machines at a price point that is an order of a magnitude higher. Unmistakably there are differences in quality, but this does not take away the fact that the commercial vendors are mostly unwilling or unable to cater the needs of consumer markets. Similarly, the thermoplastics from commercial vendors are more expensive, because it is common that these have to be acquired from approved distributors. The client is deliberately locked-in to use these sources only. This is done through technological lock-in (with chips to verify authentic cartridges) and vendors further discourage the use of alternative consumables by stressing that  this voids the warranty or will creates higher service contract fees\footnote{From personal interviews with Siert Wijnia whose employer operate such machines. Similarly, at the University of Washington, a tension between vendor and client is observed, for an example see this online discussion:\\ \url{http://open3dp.me.washington.edu/2010/08/does-this-sound-like-us-jailbreaking-print-materials/} }.
% TODO: verwerken reactie van Gerald Garnett
AM service providers didn't used to target consumer markets \citep[p.~231]{Wohlers2009}. 

\subsection{Essential function of physical prototyping}
Even though developers can carry out increasingly sophisticated computer simulations, physical prototyping remains an essential part of the design process. \citet{Thomke1998} says that simulation is beneficial to R\&D because developers can increase the diversity and frequency of problem-solving cycles while reducing the total amount of time and money spent on R\&D. 3D printing, which is called Rapid Prototyping for exactly this reason, is beneficial in exactly the same way. Advances in model making methods and in particular 3D printing are mentioned by \citet[p. 18]{ThomkeHippelFranke1998Experimentation} as being responsible for a similar reduction in time and cost of a whole variety of experiments.

Still, physical prototyping results in inevitable costs associated with material expenditure as mentioned in section \ref{protocosts}. In addition, a tangible result may be required to keep motivation high. Seeing a partially working prototype is can be highly exciting (sense of achievement) and comforting (private benefit may be achieved, time is well spent)\footnote{This is frequently observed in comments posted on Thingiverse, a website that is used to share digital designs that can be 3D printed or otherwise fabricated with automated flexible manufacturing technologies.}. This achievement can be shared at relatively low communication costs (posting a picture or Youtube movie). The revealed successes may help create momentum for further development by others. If a person knows this, it is also in his or her private benefit and justifies incurring prototyping costs even if it's still an early, proof-of-concept design without a direct use value. The revealed results build the participants' confidence that the collectively held goal can be achieved.


\section{Incentives: Benefits materialize}
Given the voluntary nature of the majority of the contributions, incentives other than monetary compensation are dominant. 59\% of contributors to open source software projects sampled by Lakhani and Wolf (2005) report that use of the output they create is one of the three most important incentives inducing them to innovate.
% TODO: hoe zit dat in de survey???
In other words, the private benefit from using it is an important benefit. This makes it important to realize that the tools to prototype can be the same tools that enable manifestation of the private utility/benefit. Due to the evolving quality of prototyping tools, better results are acquired at low costs. For an increasingly large set of products they can be competitive manufacturing tools of the end-product. Entrepreneurial users discover that they can service niche markets. This leads to community members with extrinsic monetary incentives in addition to those who are intrinsically motivated. Alternatively, it can make it more sustainable for some individuals to spend more time doing what they like. Monetary inputs to the projects can help solve some problems where prototyping is inevitably expensive.
Once it is designed, the incremental costs of sharing a design online is in many cases more than offset because others provide feedback and can further develop the design. Since the design is shared digitally, it is usually a matter of uploading a file.
% The initial nonmarket production is augmented by placing a market price on under-developed aspects of the ecosystem.
User innovators don't need to start from scratch. The task granularity determines the various sizes of tasks available to individuals with a varied level of ambition. One of the smaller tasks is bug fixing. The major incentive for a user to fixing or reporting a bug is that it improves the user and fellow users' satisfaction of the product. The private benefits may be enough to justify the effort, the social benefits (praise, reputation) further justify the effort to freely reveal the modification. Better integration of the fix in future versions made by others are another reasons for free-revealing. This is a double-edged sword: Intrinsic value of participation is at risk when there's a failure of integration of one's work into the project \citep{Benkler2002CoasesPenguin}. In other words, if your modification or fix is not accepted by the community, you might have to maintain your own local version which integrates the fix, but this version will have higher maintenance costs or will not develop further.

\section{Collaboration: Spreading the workload}
\subsection{Location}
In many cases it is more efficient to carry out several prototyping iterations in one physical location as opposed to many different people each doing a single iteration. 
On the other hand, geographically concentration limits the access to knowledge assets held by individuals who are not in this region. Reduction of the dependence on local resources increases the potential for a project to elicit contributions from a globally dispersed audience. This audience has a higher average physical proximity, but potentially a much lower social proximity. \citet{Breschi2001LocaliseKnowledgeSpills} argue that this social proximity has a significant impact on collaboration and knowledge exchange. 
% TODO: FLESH OUT!!

% Open manufacturing can be centralized 
%  (prometheus fusion) 
% but still viable. Development cost can be shared among the community through mechanisms such as "crowdfunding". Voluntary donations by those who benefit from design improvements that result from centralized prototyping (Lausersaur, Open Source Ecology, etc.). Sometime the prospect of distribution of kits (that benefit from economies of scale through centralization) may be an incentive to donate to a project. [Shah: resource sharing]




% \section{User innovation in the RepRap community}
% As mentioned in the theoretical chapter, user innovation networks can flourish under certain circumstances: 
% [Case study + Survey: Circumstance present?] 
% Presence of incentives to innovate, the means to reproduce innovations and, suitable means for users to self-production the invention. In case only the first two conditions hold, the innovation process itself still concentrates around users, yet manufacturers focus on their more favorable returns to scale \citep{VonHippelHorizInno2007}.

% Incentives
% The RepRap provides an alternative to additive manufacturing equipment that is normally available at a much higher price point. In addition motives related to cost savings, the survey revealed that motives such as learning, enjoyment, etc. were important [needs more analysis]. Researchers at Bath university had sufficient incentives and were in the lucky position of having received a research grant. 

% Reproducing others' innovations
% The Bath University groups' choice for the open source license and the documentation on the web helped others reproduce their inventions. Initially, physical prototypes that were 3D printed at Bath University in the United Kingdom were shipped to Vik Olliver, an active member based in New Zealand. At a later stage an upload and download would suffice and the object would be fabricated in the recipients home. 
% The large physical distance and timezone offset of community members makes asynchronous communications the most practical option. The benefit of most asynchronous ways of communicating is that there usually there is a record and that the information can be made available to many. People can access the information and post feedback from anywhere at any time. At first, general purpose infrastructural tools such as mailing lists, blogs, forums, wikis, public video sharing platforms (Youtube) and code repositories were deployed. At a later point a dedicated design sharing infrastructure was developed by Zach Smith, who at the time was community member by night and web-developer by day. The fabrication capability can also be considered an important infrastructural tool of open hardware developers such as those in the RepRap community.

% Production
% With physical production, scaling characteristics of production technology determine the fixed costs relative to the variable costs of a product. New manufacturing technologies (CIM, flexible manufacturing systems) can play an important role in reducing the trade-off between variety and productivityFranke N, Piller F. Configuration Toolkits for Mass Customization. International Journal of Entrepreneurship and Innovation Management (IJEIM), 2003. . These emerging technologies provide an opportunity to counter under-provisioning present in highly heterogeneous and niche markets. A lowered cost of variety is an important advantage in markets of product heterogeneity. The low fixed costs involved makes it ideally suitable for niche items when compared to mass manufacturing. 3D printing and similar digital production technologies are examples of production systems with these favorable production properties.

% Distribution
% In terms of distribution, lower-cost production technology can be more widely dispersed. This provides the opportunity to locate them closer to the user. Neigborhood-level, domestic and personal fabrication tools are located in the close vicinity of their users. Over time, a further reduction in price is likely, which makes the scenario of domestic fabricators is entirely plausible. Since domestic or personal fabricators are already available to a large proportion of the samples RepRap community, their behavior provides valuable indications of what subsequent cohorts of adopters will behave like.

% Since the emergence of open manufacturing projects like RepRap is in an industry where producers as an innovators are already established. This shows that production for markets is also viable.



%  [positive feedback loop, does this show that extreme compexity can be achieved?]

% Open design's dependence on new ICT

% Works as early as Allen (1983) show that open collaborative development of physical objects are not dependant on the information and communication technologies (ICT) that we have now. 

% Most case studies that focus on open source software show development patterns that could hardly be imagined before the advent of modern telecommunications.
% Theory shows several qualities that are important for collaborative development to flourish, which are heavily impacted by ICT.

% There have already been case studies on open development of physical inventions describing the phenomenon occurring as early as the 19th century. In principle this proves that ICT is not a requirement.
% Since there have already been case studies on open development of physical inventions (steam engine, etc.) there already is some evidence that this mode is viable. 
% Each of the inventions, either from the 19th century or the more contemporary ones, came about through communication between groups of individuals. This means that developments in communication tools and technology can have a profound impact on the amount of people that can contribute to designs and access. Larger communities can be made feasible by new ICT. Such communities can have an improved access to collectively held knowledge assets.
% The implications and reach of the phenomenon are much greater given the evolution of information and communication technology paired with the digitization of design and manufacturing.




\chapter{Conclusions}\label{Ch:Conclusions}
There are several ways in which the distributed and collaborative process of designing physical objects can be enabled. Design information needs to be shared at low cost. It is helpful if the design can actually be fabricated, because private benefits resulting from the physical outputs may be a motive. Designs that originate from users or a community can be fabricated in several ways. By a traditional manufacturer, a manufacturing service provider, or by the user itself (in a shared (FabLab) or domestic environment). Designers can adapt the design to the fabrication scenario. In case of the RepRap, domestic fabrication is made feasible.
In most non-monolithic designs, two types of components are usually found. General purpose and custom components. General purpose components are more or less standardized and can be reused after a project. Custom parts are not always a requirement, but even if it can be done with general purpose components the ability to consolidate them can make assembly much more practical. Access to custom fabrication equipment allows production of custom parts as cheap as general purpose parts.

The RepRap project already is proof that the open source development methodology also works for the design physical objects. Development of subsystems of the RepRap has been done with the assistance of physical prototyping, in several cases executed by people outside of the core team and are freely revealed under an open source license. Some of these modifications were adopted for inclusion into the main branch, but most of there were available for download for anyone who chooses to adopt it.
Encouragement and interpersonal dynamics such as on Thingiverse lead to a sustainable stream of open source design being added, and further developed by others.
% a [small/significant?] fraction of these designs are further refined by another person. 
Linus' Law, as Raymond points, out leads to more modifications because of the various perspectives, a slightly different perceptual set and analytical toolkit of the many people who keep an eye out for a project.



\addcontentsline{toc}{chapter}{Bibliography}
% or: plain,unsrt,alpha,abbrv,acm,apalike,...
\bibliographystyle{apalike}
\bibliography{library,otherpapers,/Users/erik/Documents/library}

% \opt{full}{
\pagenumbering{Roman}
% Appendices!
\appendix
\chapter{A short history of open source 3D printers}
Throughout this document I refer to the RepRap and derivatives as open source 3D printers. This appendix answers which products are included.

Because the RepRap is open source, one can easily reuse parts of the design and code to more quickly generate a variant. This process, often called forking has resulted in several derivative designs. Below these projects and their affiliation with the RepRap project are listed.

\subsubsection*{Cornell Univesity's Fab@Home}
The RepRap inspired Evan Malone and Hod Lipson at Cornell University to develop Fab@Home, a personal 3D printer that deposits material from syringes. Although the operating principle of this machine is the same, most of the mechanics and software was developed independent from the RepRap project. The Fab@Home has a BSD license, whereas RepRap uses the GPL license. While the Fab@Home project was inspired by the RepRap project, it is not a RepRap derivative. The Fab@Home is mostly open source 3D printer. Of the newest version, several of the electronics systems, PCBs and firmware are closed-source, but most of the design and new innovations that are created are freely revealed.\\
\\
Project URL: \url{http://www.fabathome.org/}

\subsubsection*{BitsFromBytes' RapMan}
BitsFromBytes, a company in the UK started selling moulded parts for the early RepRap Darwin designs. Because of high demand and because it was labor intensive to produce these kits, BitsFromBytes designed a "flat pack" version of the Darwin. This version, resulted in the RapMan, could mostly be laser-cut, which can be much faster than manual molding. Electronics were not included, and had to be sourced from various places. Later, BitsFromBytes started selling full kits. In 2009 they introduced their third major version of the RapMan, which was a fairly robust design. In early 2010 they released the RapMan Pro. It was mostly developed internally by BitsFromBytes, though. In April 2010 they launched the BfB 3000, a fully assembled 3D printer for 1,995 GBP. While starting out with a design based on the RepRap Darwin model, BitsFromBytes have created their own design files and have not been releasing their designs on a frequent basis. Nor are they fully involving the community in the design process. For this reason, recent RapMan versions cannot be said to be open source 3D printers.\\
\\
Company URL: \url{http://www.bitsfrombytes.com/}

\subsubsection*{Evil Mad Scientists' CandyFab}
Evil Mad Scientists developed the CandyFab 6000. Diffusion of these machines has not been reported.\\
\\
Project URL: \url{http://www.candyfab.org/}

\subsubsection*{Makerbot Industries' Cupcake CNC}
Makerbot Industries shipped a first batch of their Cupcake CNC in April 2009\footnote{Source: http://blog.makerbot.com/2009/04/16/how-to-ship-makerbots/}. By the end of 2009 they had shipped nearly 500 complete kits. They have been working hard to ramp up production in order to keep up with demand. After operating for a year they had sold about 1000 kits in April 2010. The RepRap community and Makerbot industries have a close relationship, due to the people involved and due to their adherence to open source practices. Zach Smith, on of the co-founders of Makerbot Industries had always been a very active participant in the RepRap community almost since early 2006.\\
\\
Company URL: \url{http://www.makerbot.com/}

% \subsubsection*{CubeSpawn}
% CubeSpawn

% \subsubsection*{Contraptor}
% \subsubsection*{Shapercube}
% Company URL: http://shapercube.com/
% \subsubsection*{}
% \subsubsection*{}
% \subsubsection*{}
% \subsubsection*{UP!}


\subsubsection*{Ultimaker's Protobox}
The Ultimaker Protobox originated out of a RepRap workshop at a FabLab in Utrecht, the Netherlands. The aim was to make the machine easier to build. It is assembled from traditionally manufactured plywood sheets that are digitally laser-cut. The machine is currently in the stage just before it is going to be be sold. The design for the Ultimaker released under an open source license.\\
\\
Project URL: \url{http://www.ultimaker.com/}
% } % history of OSS 3D printers

\chapter{List of community innovations}
\label{apdx:innovationList}This section contains categories of innovations that were identified in the RepRap project and one or more examples per category.% \include{innovations2}
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\begin{flushleft}
\tablehead{}
\begin{supertabular}{|m{1.6504599in}|m{4.9191597in}|}
\hline
\bfseries Type of improvement &
\bfseries Example(s) from the RepRap case study\\\hline
Added functionality &
\liststyleLi
\begin{itemize}
\item The ability to remove material in addition to adding it. The
ability to mix multiple materials. Use of ceramics and pastes instead
of thermoplastics.\item Embedding wire and conductive materials.\item
Ability to combine additive and subtractive manufacturing
(Hydra-MMM)\end{itemize}
\\\hline
Improved existing functionality &
\liststyleLii
\begin{itemize}
\item Faster, more efficient, more detailed and/or stronger
output.\end{itemize}
\\\hline
Increased ease of assembly and use &
\liststyleLiii
\begin{itemize}
\item
Derivative designs such as RepRap Mendel, Makerbot and Ultimaker
Protobox.\end{itemize}\\\hline
Lower cost &
\liststyleLiv
\begin{itemize}
\item Design of an alternative belt drive mechanism.\item Allowing the
use of cheap skate bearings\end{itemize}
\\\hline
\end{supertabular}
\end{flushleft}
\pagebreak
\begin{flushleft}
\tablehead{}
\begin{supertabular}{|m{1.6504599in}|m{4.9191597in}|}
\hline
\bfseries Type of improvement &
\bfseries Example(s) from the RepRap case study\\\hline
More suitable components (e.g. easier-to-acquire) &
\liststyleLv
\begin{itemize}
\item A drive system based on ubiquitous ball-chains as an alternative
to industrial timing belt and pulleys.\item The Sanguino was developed
as an alternative to the Arduino.\end{itemize}
\\\hline
Specialization towards a certain application &
\liststyleLvi
\begin{itemize}
\item Digital pottery system\item Plant growth modeling
device\end{itemize}
\\\hline
Interoperability with other systems &
\liststyleLvii
\begin{itemize}
\item Compatibility with G-Code common in industrial CNC
installations.~\item Writing platform independent software.~\item
Adding USB interfaces and having the machine work independently from
removable storage media.\end{itemize}
\\\hline
Improved design architecture (e.g. modularization, part consolidation) &
\liststyleLviii
\begin{itemize}
\item Adoption of industrial standards for NC-machine control.\item
Change from multiple independent microcontroller in a token ring to a
single master microcontroller architecture with an optional slave
extruder controller.\end{itemize}
\\\hline
Refining operating techniques &
\liststyleLix
\begin{itemize}
\item Sharing better settings for making parts easier to separate from
their support structure (if applicable)\end{itemize}
\\\hline
Improved sharing infrastructure &
\liststyleLx
\begin{itemize}
\item Thingiverse.com was developed as website to facilitate sharing of
digital designs for physical objects and currently hosts over 3000 user
contributed objects which include, documentation, discussions and the
data to manufacture them or make derivative designs.\item Adoption of
Wiki{\textquotesingle}s and blogs for knowledge sharing.\item Local
user groups\end{itemize}
\\\hline
\end{supertabular}
\end{flushleft}


\chapter{Community Survey\label{apdx:survey}}

% \include{survey_simple}
\include{survey}


\end{document}
