Researchers can build craft-aligned digital fabrication technologies by designing interfaces inspired by craft tools. This process often demands real-time physical interactions not supported by today’s automation-focused CNC control systems. We theorize we can lower engineering challenges for craft-aligned CNC prototyping by allowing designers to modify existing CNCs to support both automated and real-time control. We contribute a new creative motion control system, Stepdance, which consists of two elements: 1) modular controllers that replace the G-code controller of a CNC and can be chained together to develop new interfaces, and 2) a modular programming library that supports declarative mappings between live user input, pre-programmed operations, and machine motion. We developed Stepdance with practitioners at the Haystack Mountain School of Craft, where we used the system to modify commercial plotters and 3D printers. We analyze the resulting artifacts, interactions, and ideas to discuss how Stepdance can broaden the practice of CNC design via physical metaphor.

Skilled potters use manual tools with direct material engagement. In contrast, the design of clay 3D printers and workflows reinforces industrial CNC manufacturing conventions. To understand how digital fabrication can serve skilled craft practitioners, we ask: how might clay 3D printing function if it had evolved from traditional pottery tools? To examine this question, we created the Digital Pottery Wheel (DPW), a throwing wheel with 3D printing capabilities. The DPW consists of a polar mechanical architecture that looks and functions like a pottery wheel while supporting 3D printing and a real-time modular control system that blends automated and manual control. We worked with ceramicists to develop interactions that include printing onto thrown forms, throwing to manipulate printed forms, and integrating manual control, recording, and playback to re-execute manually produced forms. We demonstrate how using a physical metaphor to guide digital fabrication machine design results in new products, workflows, and perceptions.

Software-first digital fabrication workflows are often at odds with material-driven approaches to design. Material-driven design is especially critical in manual ceramics, where the craftsperson shapes the form through hands-on engagement. We present the Craft-Aligned Scanner (CAS), a 3D scanning and clay-3D printing system that enables practitioners to design for digital fabrication through traditional pottery techniques. The CAS augments a pottery wheel that has 3D printing capabilities with a precision distance sensor on a vertically oriented linear axis. By increasing the height of the sensor as the wheel turns, we directly synthesize a 3D spiralized toolpath from the geometry of the object on the wheel, enabling the craftsperson to immediately transition from manual fabrication to 3D printing without leaving the tool. We develop new digital fabrication workflows with CAS to augment scanned forms with functional features and add both procedurally and real-time-generated surface textures. CAS demonstrates how 3D printers can support material-first digital fabrication design without foregoing the expressive possibilities of software-based design.

Digital fabrication machines (such as laser cutters or 3D printers) can be instructed to produce any part geometry within their application space. However, machines' application spaces are not easily modified or extended. How can we enable the production of application-specific computer-controlled machines by machine building novices? How can we facilitate rapid prototyping of rapid prototyping tools? We propose a novel set of modules, the Cardboard Machine Kit, for the construction of digital fabrication machines. These open-source modules are implemented using cardboard frames, stepper motors, and networked electronics controlled through a Python library. We evaluated the kit both through machine building workshops and by studying the usage of the kit in the wild. In the wild we observed more than 500 novice machine builders who built 125 different machines for 15 different application types. We argue that this breadth demonstrates the efficacy of this modular approach. Finally we discuss the limitations of the Cardboard Machine Kit and discuss how it could inform future machine building infrastructure.

We present a case study of Popfab, a portable multi-purpose digital fabrication tool. It is uses interchangeable heads (3D printer, CNC mill, and CNC knife) on a general-purpose motion platform that folds into a briefcase. Popfab contributed to the discussion of the future of digital fabrication tools by demonstrating the feasibility of both portability and both additive and subtractive manufacturing on a single platform. Portability is not yet a widely considered option for digital fabrication tools, but with Popfab we demonstrate that general site-specific personal fabrication is possible.

Many kinds of digital fabrication are accomplished by precisely moving a tool along a digitally-specified path. This precise motion is typically accomplished fully automatically using a computer-controlled multi-axis stage. With that approach, one can only create objects smaller than the positioning stage, and large stages can be quite expensive. We propose a new approach to precise positioning of a tool that combines manual and automatic positioning: in our approach, the user coarsely positions a frame containing the tool in an approximation of the desired path, while the device tracks the frame's location and adjusts the position of the tool within the frame to correct the user's positioning error in real time. Because the automatic positioning need only cover the range of the human's positioning error, this frame can be small and inexpensive, and because the human has unlimited range, such a frame can be used to precisely position tools over an unlimited range.