Mixed Physical and Virtual Design Environments for Digital Fabrication Christian Weichel B.Sc. Hochschule Furtwangen University This dissertation is submitted for the degree of Doctor of Philosophy School of Computing and Communications Lancaster University September 2015 ❉❡❝❧❛❛✐♦♥ I hereby declare that except where specific reference is made to the work of others, the contents of this dissertation are original and have not been submitted in whole or in part for consideration for any other degree or qualification in this, or any other university. This dissertation is my own work and contains nothing which is the outcome of work done in collaboration with others, except as listed below. All of this work was done under the supervision of Hans Gellersen. Chapter 3 contains work done in collaboration with Manfred Lau. Chapter 4 contains work done in collabora- tion with Jason Alexander and Abhijit Karnik. Chapter 5 contains work done in collabora- tion with Manfred Lau and David Kim. Chapter 6 contains work done in collaboration with John Hardy and Jason Alexander. Christian Weichel September 2015 Es ist nicht nur der Künstler, der alles Größte in seinem Leben der Phantasie verdankt, sondern überhaupt jeder schöpferische Mensch. Das dynamische Prinzip der Phantasie ist das Spielerische, das auch dem Kinde eignet, und als solches ebenfalls unvereinbar mit dem Prinzip ernster Arbeit erscheint. Aber ohne dieses Spiel mit Phantasien ist noch nie ein schöpferisches Werk geboren worden. Wir verdanken dem Imagionationsspiel unabsehbar viel. It is not only the artist, who owes all great things in his life to fantasy, but indeed every creative person. The dynamic principle of fantasy is play, which also suits the child, and as such seems irreconcilable with the principle of serious work. However, without this play with fantasies, no creative work has ever been born. We owe the play with imagination incalculably. – Carl Jung [1, p. 65] ❆❝❦♥♦✇❧❡❞❣❡♠❡♥ This thesis has one author, yet it is an achievement of many. Without any one of the below mentioned – and the countless many who remain unnamed – none of this would exist. Firstly, I would like to thank my supervisor Hans Gellersen for giving me the opportu- nity to pursue this research endeavor in the first place; for giving me the freedom to engage in a topic of my own choosing. Thank you for your support, supervision and patience through- out the past four years. Second, I am indebted to my second supervisor Jason Alexander for supporting me throughout this thesis, especially during the final phase. Thank you very much for you invaluable feedback and advice. Third, thank you Manfred Lau for helping me get started in this topic. I have found all our discussions invaluable. Secondly, I am grateful to all members of the EIS group (and beyond) who I am honored to call my friends. One would be hard pressed to find an environment more welcoming, friendly, stimulating and supportive than this group. Thank you for the countless discus- sions, encouragement and support. Pauline Anthonysamy and Mélodie Vidal, thank you for becoming close friends, for the many conversations and hugs. Mélodie and Ken Pfeuffer, thank you for sharing many great hours and our house(s). John Hardy, thank you for making this stressful last build a pleasant experience through your open cordiality. Thanks to Steven Houben for introducing me to HCI theory and for our philosophy of science discussions. Also thanks to all iCareNet members who made this journey even more enjoyable. Thirdly, I am forever indebted to my family: to my sisters Agnes and Stefanie, to my partner Ioana and my parents Ruth and Bernhard. The latter two who have been, and con- tinue to be, more influential to me than anyone else. Thank you for your steady support, and believing in me. I can not overstate my gratitude. Ioana, you manage to keep me grounded when I need it most; it will be my greatest joy to spend a life with you. To my parents. To Ioana. ❆❜❛❝ Digital Fabrication (3D printing, laser-cutting or CNC milling) enables the automated fab- rication of physical objects from digital models. This technology is becoming more readily available and ubiquitous, as digital fabrication machines become more capable and afford- able. When it comes to designing the objects that are to be fabricated however, there are still barriers for novices and inconveniences for experts. Through digital fabrication, physical objects are created from digital models. The digital models are currently designed in virtual design environments, which separates the world we design in from the world we design for. This separation hampers design processes of experienced users and presents barriers to novices. For example, manipulating objects in virtual spaces is difficult, but comes naturally in the physical world. Further, in a virtual environment, we cannot easily integrate existing physical objects or experience the object we are designing in its future context (e.g., try out a game controller during design). This lack of reflection impedes designer’s spatial understanding in virtual design environments. To enable our virtual creations to become physical reality, we have to posses an ample amount of design and engineering knowledge, which further steepens the learning curve for novices. Lastly, as we are physically separated from our creation – until it is fabricated – we loose direct engagement with the material and object itself, impacting creativity. We follow a research through design approach, in which we take up the role as inter- action designers and engineers. Based on four novel interaction concepts, we explore how the physical world and design environments can be brought closer together, and address the problems caused their prior separation. As engineers, we implement each of these concepts in a prototype system, demonstrating that they can be implemented. Using the systems, we evaluate the concepts and how the concepts alleviate the aforementioned problems, and that the design systems we create are capable of producing useful objects. In this thesis, we make four main contributions to the body of digital fabrication related v Human-Computer Interaction (HCI) knowledge. Each contribution consists of an interac- tion concept which addresses a subset of the problems, caused by the separation of virtual design environment, and physical target world. We evaluate the concepts through prototype implementations, example walkthroughs and where appropriate user-studies, demonstrating how the concepts alleviate the problems they address. For each concept and system, we describe the design rationale, and present technical contributions towards their implementa- tion. The results of this thesis have implications for different user audiences, design processes, the artifacts users design and domains outside of digital fabrication. Through our concepts and systems, we lower barriers for novices to utilize digital fabrication. For experienced designers, we make existing design processes more convenient and efficient. We ease the design of artifacts that reuse existing objects, or that combine organic and geometrically structured design. Lastly, the novel interaction concepts (and on a technical level, the sys- tems) we present, which blur the lines between physical and virtual space, can serve as basis for future interaction design and HCI research. ✉❜❧✐❝❛✐♦♥ • Christian Weichel, John Hardy, Jason Alexander and Hans Gellersen. 2015. Re- Form: Integrating Physical and Digital Design through Bidirectional Fabrication. In Proceedings of the 28th annual ACM symposium on User interface software and tech- nology (UIST ’15). • Christian Weichel, Jason Alexander, Abhijit Karnik and Hans Gellersen. 2015. SPATA: Spatio-Tangible Tools for Fabrication-Aware Design. In Proceedings of the Ninth In- ternational Conference on Tangible, Embedded, and Embodied Interaction (TEI ’14). • Christian Weichel, Manfred Lau, David Kim, Nicolas Villar and Hans Gellersen. 2014. MixFab: A Mixed-Reality Environment for Personal Fabrication. In Proceed- ings of the SIGCHI Conference on Human Factors in Computing Systems (CHI ’14). • Christian Weichel, Manfred Lau and Hans Gellersen. 2013. Enclosed: A Component- Centric Interface for Designing Prototype Enclosures. In Proceedings of the 7th In- ternational Conference on Tangible, Embedded and Embodied Interaction (TEI ’13). • Christian Weichel, Jason Alexander, Abhijit Karnik and Hans Gellersen. 2015. Con- nected Tools in Digital Design. IEEE Pervasive Computing 14, 2 (April 2015), 18-21. • Christian Weichel, Jason Alexander and John Hardy. 2015. Shape Display Shader Language (SDSL): A New Programming Model for Shape Changing Displays. In Proceedings of the 33rd Annual ACM Conference Extended Abstracts on Human Factors in Computing Systems (CHI EA ’15). • John Hardy, Christian Weichel, Faisal Taher, John Vidler and Jason Alexander. 2015. ShapeClip: Towards Rapid Prototyping with Shape-Changing Displays for Designers. vii In Proceedings of the 33rd Annual ACM Conference on Human Factors in Computing Systems (CHI ’15). • Faisal Taher, John Hardy, Abhijit Karnik, Christian Weichel, Yvonne Jansen, Kasper Hornbæk, and Jason Alexander. 2015. Exploring Interactions with Physically Dy- namic Bar Charts. In Proceedings of the 33rd Annual ACM Conference on Human Factors in Computing Systems (CHI ’15). • Manfred Lau, Christian Weichel, and Nicolas Villar. 2013. Workshop on personal and pervasive fabrication (PerFab 2013). In Proceedings of the 2013 ACM conference on Pervasive