SCF '22: Symposium on Computational Fabrication

Full Citation in the ACM Digital Library

SESSION: Full Papers

Computational Support for Multiplicity in Hierarchical Electronics Design

While hierarchical design promises design process improvements through structures that better enable computational design, the basic model of blocks, ports, and connections lacks support for multiplicity – dealing with repeated instances of objects. In this work, we explore two extensions of that basic model to support two types of multiplicity, specifically in the context of board-level electronics where this is a common pattern. First, to support blocks that can be arbitrarily scalable across number of devices – e.g., an n-element LED array generator – we extend the existing fixed port interfaces for blocks with port arrays that can have dynamic width with automatic propagation through connections. Second, to support mapping abstract blocks in a design onto physical multipack devices – e.g., combining resistors across the design into a single quad-pack resistor device to optimize for fabrication – we introduce cross-hierarchy packing including support for shared pins. For both of these constructs, we describe the user-facing abstractions, internal representations, and compiler implementation, then demonstrate their end-to-end use through three example designs that we have fabricated and tested.

Craft-Inspired Digital Fabrication: A Study of Interactive Robotic Clay Carving

Digital fabrication workflow is typically linear that starts from ideating a design form via 3d-modelling or programming, later ends fabricating this predetermined design form. In this linear workflow, design ideation must finish before making/fabrication begins. As a result, designers often miss the opportunity to design with material affordances, such as discovering and incorporating intricate material expressions that can only emerge through an enactive and embodied process of making. Knowing that such process of making forms the cornerstone of craft, this study investigates how digital fabrication can gain craft-like qualities by allowing material expressions to be gradually discovered and mastered. We thus developed an interactive fabrication system by integrating force feedback into a robotic clay carving process. Real-time force feedback allows improvisational control of carving actions by manually interacting with the robotic end effector on-the-fly. Accordingly, carved clay expressions are continuously modified during fabrication. Our results demonstrate that this approach allows intricate material expressions to serendipitously appear, which in turn inspire new design ideas to form and gradually develop. Our contributions include: 1) a new enactive and embodied interaction modality that continuously regenerates a self-similar fabrication action sequence so that its design space can be gradually learned; 2) a craft-inspired digital fabrication workflow that supports on-the-fly design ideation by sequentially sketching, isolating, and composing an intricate material expression; and 3) a collection of critical considerations that propose how our findings could help integrate more improvisation, serendipity, and reflection in digital fabrication.

A Collaborative Multi-robot Platform for the Distributed Fabrication of Three-dimensional Fibrous Networks (Spatial Lacing)

This research presents a collaborative multi-robot strategy for the distributed fabrication of Spatial Lacing - a novel system of lightweight, multi-topology fiber structures enabled by parallel manipulation of filament materials. The parallelized fabrication logic, which takes inspiration from textile production methods, is inherently different from existing construction techniques using continuous filaments and poses new challenges for fabrication. The paper proposes a distributed cyber-physical platform with mobile robots that can exceed size and flexibility limitations of industrial machinery. A hybrid behavior-based control schema is developed where robotic behaviors are abstracted from the traditional textile craft of bobbin lace-making and adapted for robotic execution through coordinated collaborative action sequences, creating a new robotic action space for filament structures. Parallel task execution, real-time sensor feedback, and the coordination of multiple distributed agents is achieved through a multi-threaded software architecture. This paper focuses on the development of the cyber-physical fabrication platform including custom robotic hardware, derivation of robotic behaviors, task generation and coordination, and multi-agent communication protocols. The research finds its point of departure from textile craft processes and demonstrates new potentials in construction with filament materials when multi-robot systems perform coordinated tasks that depend on simultaneous actions. It culminates in the choreography of two mobile robots performing actions required to create a Spatial Lacing node in a parallel, coordinated fashion.

Efficient Layer-by-Layer Simulation for Topology Optimization

Topology optimization and additive manufacturing together enable the optimal design and direct fabrication of complex geometric parts with groundbreaking performance for diverse applications. However constraining the optimization to ensure that the generated object can be reliably manufactured via layer-by-layer 3D printing processes is challenging. The typical solution is to enforce design rules based only on geometric heuristics like overhang angles, minimum wall widths, and maximum bridge spans. Recent work has proposed instead to simulate the robustness of each partial object generated from bottom-to-top during the fabrication process as a more accurate, physics-aware printability assessment. However, this approach comes at the cost of an vast increase in the number of simulations run per design iteration, making existing implementations intractable at high resolution. We demonstrate that by developing a custom solver leveraging the close relationships between these many simulations, even voxel-level layer-by-layer simulations are feasible to incorporate into high-resolution 2D and 3D topology optimization problems on a single workstation.

AmiGo: Computational Design of Amigurumi Crochet Patterns

We propose an approach for generating crochet instructions (patterns) from an input 3D model. We focus on Amigurumi, which are knitted stuffed toys. Given a closed triangle mesh, and a single point specified by the user, we generate crochet instructions, which when knitted and stuffed result in a toy similar to the input geometry. Our approach relies on constructing the geometry and connectivity of a Crochet Graph, which is then translated into a crochet pattern. We segment the shape automatically into chrochetable components, which are connected using the join-as-you-go method, requiring no additional sewing. We demonstrate that our method is applicable to a large variety of shapes and geometries, and yields easily crochetable patterns.

Simulation of printed-on-fabric assemblies

Printing-on-fabric is an affordable and practical method for creating self-actuated deployable surfaces: thin strips of plastic are deposited on top of a pre-stretched piece of fabric using a commodity 3D printer; the structure, once released, morphs to a programmed 3D shape. Several physics-aware modeling tools have recently been proposed to help designing such surfaces. However, existing simulators do not capture well all the deformations these structures can exhibit. In this work, we propose a new model for simulating printed-on-fabric composites based on a tailored bilayer formulation for modeling plastic-on-top-of-fabric strips, and an extended Saint-Venant–Kirchhoff material law for modeling the surrounding stretchy fabric. We show how to calibrate our model through a series of standard experiments. Finally, we demonstrate the improved accuracy of our simulator by conducting various tests.

DancingPottery: Posture-Driven Pottery Generative Design and Fabrication

We present a method of designing and fabricating pottery artwork through human posture where the users need neither professional skills nor experience with 3D modeling software. This method creatively solves the problem of mapping between the human skeleton and the pottery shape and has a strong ability to model complex shapes while being user-friendly. Our system represents the deformation of a pottery object with four independent operators and provides real-time visual feedback as the user changes their posture. Unlike traditional pottery throwing, where the product has high symmetry, our system supports modeling asymmetric pottery shapes. After obtaining the model, the model can be fabricated directly via ceramic 3D printing, as the models satisfy printability constraints. A user study showed that the designed mapping relationship supports pottery shape deformation with a high degree-of-freedom, and inexperienced users can easily use the system with minimal instruction.

Improving Programming for Exploratory Digital Fabrication with Inline Machine Control and Styled Toolpath Visualizations

Makers from increasingly diverse backgrounds use digital fabrication machines to explore novel design spaces. However, software tools for fabrication are designed primarily for replication-based tasks; programming machines for bespoke applications while accounting for physical contingencies remains challenging. To better support exploratory fabrication, we present Verso, a proof-of-concept approach that extends concepts from computational notebooks. Verso affords graphical control via modules that result in continuous feedback, letting makers fluidly view and iterate on their workflows. Modules also provide controlled synchronization between code and external digital and physical processes while preserving a clear flow of data. Toolpath stylesheets (TSS) translate machine instructions into task-specific visualizations that can be projected into the machine’s physical work space. To demonstrate our approach, we synthesize three design goals and propose three example exploratory workflows for subtractive manufacturing, materials science, and biology.

NozMod: Nozzle Modification for Efficient FDM 3D Printing

3D printing is based on layered manufacturing, where the layers are printed consecutively in increasing height order. In Fused Depositing Modeling (FDM), the printing head may travel without extruding material between separated “islands” of the sliced layers. These travel movements increase the printing time and reduce the quality of the 3D printed part. We present an extended nozzle modification, which can be applied to off-the-shelf FDM printers, and a corresponding toolpath generation algorithm. Together, these dramatically reduce the amount of travel movement, thus improving the printing time and quality of the results. The extended nozzle allows us to print the sliced layers out of order, where part of a lower layer might be printed after a higher layer was already printed. Our toolpath generation algorithm takes advantage of this capability and generates a toolpath which maximizes the number of consecutive layers printed within the same “island” without requiring any travel movement. In addition, the algorithm optimizes the order of the printed islands, and guarantees that the generated toolpath will not cause collisions between the extended nozzle and the model. We demonstrate our approach on a collection of varied models, and show that we considerably reduce the required travel, and improve the printing time and quality compared to standard layer-by-layer printing.

Structure-Preserving Editing of Plates and Volumes for Laser Cutting

We present a 3D editor for laser cutting that extends the range of models that users can manipulate. Our system gives users control over the detailed elements of laser cutting, i.e., individual plates and the associated joints, yet at the same time also allows for efficient editing by means of volumetric tools while preserving the structure of plates in the model. Our system consists of four functional groups: (1) We started with a fabrication-aware 3D editor capable of handling volumetric models (kyub, Baudisch et al., 2019). This subsystem represents 3D models as a single volume. (2) We added a second subsystem that represents laser-cut models as an arrangement of plates in 3D. This allowed us to add tools that allow manipulating individual plates. (3) We unified these two subsystems by adding a demotion mechanism that breaks volumes down into multiple plates, to allow users to apply plate tools to volumes, as well as (4) a promotion mechanism, which infers volumetric substructures from sets of plates, to allow users to apply volume-based tools to plate structures. We validated the resulting system by recreating the 100-model benchmark of assembler3 (Roumen et al., 2021a). Our combined system successfully recreated 87 of the models, compared to 9 with a volume-only baseline system (kyub) and 15 with a plate-only baseline system (flatFitFab, McCrae et al., 2014).

SVG-PCB: a web-based bidirectional electronics board editor

We present an open-source, web-based, client-side editor for parametric printed circuit board (PCB) design which supports bidirectional editing between our JavaScript hardware description language and a direct manipulation graphical interface. We developed a JSON format for describing component pads as SVG path data strings, referential component placements, and wire descriptions with curves, arbitrary degree Bezier splines, fillets, and chamfers. Boards can be exported in their JavaScript representation, as SVGs, or in Gerber format. The web-editor also supports interactive elements which update PCB designs in real-time such as number sliders, component translation handles, and drag-and-drop component libraries. Our tool was successfully used for developing and sharing basic boards in a distributed global class on digital fabrication and by researchers to produce procedurally generated designs. SVG-PCB offers the power and flexibility of a general purpose programming language for designing boards with the ease of use of a graphical user interface.

A Computational Fabrication Course: Exploring Philosophical Reflection, Real-World Use, Personal Expression, and Social Connection

Computational Fabrication—the creation of physical objects via programming and digital fabrication—is emerging as an important research area in human computer interaction and other computing domains. This paper describes a new semester-long course on the topic. We introduce the course and discuss emergent themes. We argue that computational fabrication can provide unique educational experiences, including opportunities for integrating computation with philosophical reflection, personal expression, real-world use, and social connection. We believe these affordances are noteworthy in the context of education, particularly computer science education, and suggest exciting research topics about the social dimensions of computational fabrication that could be explored in more depth.

SESSION: Demo Abstracts

Advanced Pathing for Additive Manufacturing

In Additive Manufacturing (AM), slicing is the process of dividing a solid body CAD (computer aided design) object into layers by "slicing" the object with a horizontal plane. After the object is cut into layers, toolpaths can be planned for each layer and exported as g-code in a text file that a 3D printer can read. The basic slicing process has been around for many years and has been optimized such that simple models can be sliced in under ten seconds. As 3D printers evolve and new hardware capabilities are developed, advanced software solutions are needed to create the toolpaths to support these systems. This demo will outline four advanced pathing solutions for additive manufacturing including site specific control meshes, adding a degree of freedom to the pathing, real-time control with augmented reality, and automated DXF (drawing exchange format) slicing and packing.

Applications of a Machine Embroidered Metamaterial

The ability to easily create embroidered lace textile objects that can be manipulated in structured ways, i.e., metamaterials, could enable a wide variety of applications from interactive buttons to physical therapy devices. In this demo we show how freestanding machine embroidered lace can create metamaterials objects that use out-of plane kirigami and auxetic effects. We demonstrate a kirigami button and several applications of auxetic lace.

Applied Viscous Thread Instability for Manufacturing 3D Printed Foams

Traditional foams are fabricated via stochastic chemical processes that yield homogeneous material properties. Foams can exhibit a wide range of material properties by varying process controls allowing them to be used in many industrial and commercial applications. Previously, additive manufacturing could only produce foam approximations in the form of traditional lattice infill. Our work employs viscous thread printing (VTP) on a fused filament fabrication (FFF) printer, exploiting the semi-viscous nature of extruded filament to coil producing a new type of printed foam. The use of 3D printing in this application allows for significant advantages: spatial control of extrusion allows for graded material properties and custom foam shapes on-the-fly.

Bubbling Up Form from Data: A Nature-Inspired Form Generation Tool

We present a novel form-generation tool inspired by the natural phenomena of methane gas trapped in frozen lakes. To demonstrate its potential we discuss several installations designed by connecting our tool to a variety of data sources to seed form generation.

Demo paper: Craft-inspired digital fabrication with a study of interactive robotic clay carving

This demonstration presents craft-inspired digital fabrication that is enabled by a human-robot interaction modality, regeneration, as introduced in our SCF 2022 paper. Regeneration refers to executing a self-similar robotic action sequence at differing positions on the material based on real-time human interaction. The concept of regeneration is grounded in the crafting process, in which intricate material behaviours are incorporated into artefacts by way of repeated actions. Accordingly, our demonstration will show how regeneration allows exploring material behaviours as part of design process in digital fabrication. Our demo session includes: 1) an explanatory video showing recordings of interactive robotic clay carving by way of regeneration, 2) a small collection of robotically carved clay tiles, 3) a poster that graphically explains regeneration interaction modality and how it supports to explore material behaviour during digital fabrication.

Demonstrating a Fabricatable Bioreactor Toolkit for Small-Scale Biochemical Automation

Biological and chemical engineering creates novel materials through custom workflows. Supporting such materials development through systems research such as toolkits and software is increasingly of interest to HCI. Bioreactors are widely used systems which can grow materials, converting feedstock into valuable products through fermentation. However, integrated bioreactors are difficult to design and program. We present a modular toolkit for developing custom bioreactors. Our toolkit contains custom hardware and software for adding chemicals, monitoring the mixture, and refining outputs. We demonstrate our bioreactor toolkit with a beer brewing application, an automated process which involves several biochemical reactions that are comparable to other synthetic biology processes.

Demonstrating Dynamic Toolchains for Machine Control

Humans are increasingly able to work side-by-side with desktop-scale digital fabrication machines. However, much of the software for controlling these machines does not support live, interactive exploration of their capabilities. We present Dynamic Toolchains, an extensible development framework for building parametric machine control interfaces from reusable modules. Toolchains are built and run in a live environment, removing the repetitive import and export bottleneck between software programs. This enables humans to easily explore how they can use machine precision to manipulate physical materials and achieve unique aesthetic outcomes. In this demonstration, we build a toolchain for computer-controlled watercolor painting and show how it facilitates rapid iteration on brush stroke patterns.

Demonstrating p5.fab: Direct Control of Digital Fabrication Machines from a Creative Coding Environment

Machine settings and tuning are critical for digital fabrication outcomes. However, exploring these parameters is non-trivial. We seek to enable exploration of the full design space of digital fabrication. To do so, we built p5.fab, a system for controlling digital fabrication machines from the creative coding environment p5.js and informed by a qualitative study of 3D printer maintenance practices. p5.fab prioritizes material exploration, fine-tuned control, and iteration in fabrication workflows. We demonstrate p5.fab with examples of 3D prints that cannot be made with traditional 3D printing software, including delicate bridging structures and prints on top of existing objects.

Demonstration of Fibercuit: Techniques to Prototype High-Resolution Flexible and Kirigami Circuits with a Fiber Laser Engraver

In this demonstration, we showcase Fibercuit [Yan et al. 2022], a set of rapid prototyping techniques to fabricate high-resolution, flexible, and kirigami circuits using a fiber laser engraver. A set of examples will be presented in this demo, including custom dice, flex cables, custom end-stop switches, electromagnetic coils, LED earrings and a kirigami crane circuit designed and fabricated using our techniques.

Embodied Calligraphy Learning through Direct Kinesthetic Feedback

Crafts such as writing calligraphy require not only arduous practices to achieve mastery but also emphasize an individual’s expression through the practice. Calligraphy learning traditionally involves observing and copying expert manuscripts where learners obtain muscle control through repetitive practices. Learners often rely on comparing the visual differences in the output and adjust until they have achieved similar results. We propose a system that engages a calligraphy learner or audience with an actuated brush that reflects the movement of the artist during writing. We describe the details of the design of the system and interaction scenarios, insights gathered from public showcases on aspects such as agency, and the next steps for constructing a movement database.

Enhancing access to high quality tangible information through machine embroidered tactile graphics

FabHacks: A Domain-specific Language for Functional Fixtures Using Everyday Objects

In everyday life, it is common that a temporary solution is needed for a task such as storage and organizing. Instead of purchasing commercial items that are specifically designed for these tasks, more and more people tend to DIY something with what they have on hand – which we call a “hack". To design a hack is not as straightforward, however, because it requires creativity to come up with ways of combining objects, and also understanding how objects interact and whether the design is physically valid.

We conduct a formative study of “home hacks" – functional assemblies that can be made with household items. Based on the insights from the study, we create a domain-specific language for representing fixture designs, as well as an interface for users to visualize and explore the possible configurations of their designs. This demo showcases the interactive tool in which users can play with example hack designs and one fabricated example built according to a design represented in the DSL.

Fabricating Accessible Designs with Knitting Machines

Knitting machines have the power to manufacture and customize fabrics quickly, but today’s proprietary knitting design systems are challenging to use and inaccessible to common users. Research advances have improved the desgin process, but tend to focus on designing from scratch rather than modification. We present a knitting design pipeline that given a KnitGraph representation of a desirable knit object as input, enables users to 1) modify a KnitGraph to add holes and pockets, which can enhance a design or make it more accessible to people with disabilities and 2) generate corresponding low-level machine commands readable by the knitting machine based on the modified KnitGraph.

Generative co-design for microfluidics-accelerated 3D printing

Increasing the speed of 3D printing is critical for its widespread adoption as a manufacturing technique. A recently-introduced multi-material 3D printing process called injection CLIP has been shown to accelerate printing by nearly an order of magnitude using computationally-designed microfluidic networks. However, automated design tools for 3D microfluidics have lagged far behind increasing fabrication capabilities and needs. Here, to facilitate the study and application of this novel printing process, we present a fluid dynamics-informed generative design tool for microfluidic networks based on native CAD geometries.

Hierarchical Computational Design of Board-Level Electronics

While there has been much work on hierarchical and computational design for mechanical structures, much less has been done on the electronics side despite being an integral part of many modern devices. Our work explores how to make board-level electronics design easier and more accessible by raising the level of design from components to functional blocks. To enable this, we take a hardware description language (HDL) approach that enables experts to build libraries of subcircuits and package them in a way to be usable by more novice users. Recent language constructs supporting multiplicity – dealing with repeated instances of objects – further enhance the power of this system. This demo includes both physical example hardware that we have built using this system, as well as live and interactive demonstrations of the system including supporting tooling in the form of an integrated development environment (IDE).

Knitting 4D Garments with Elasticity Controlled for Body Motion

In this paper, we present a new computational pipeline for designing and fabricating 4D garments as knitwear that considers comfort during body movement. This is achieved by careful control of elasticity distribution to reduce uncomfortable pressure and unwanted sliding caused by body motion. We exploit the ability to knit patterns in different elastic levels by single-jersey jacquard (SJJ) with two yarns. We design the distribution of elasticity for a garment by physics-based computation, the optimized elasticity on the garment is then converted into instructions for a digital knitting machine by two algorithms proposed in this paper.

On Designing Stools, Scripted Decisions

To further understand the necessary factors and characteristics of design fabrication from the designers’ end, we wrote a stool generator using Grasshopper script within the Rhinoceros 3D modeling environment. This work produces a script that becomes a design tool to automatically generate multiple stool designs. We explain and illustrate the design components, demonstrate and show an example design, and discuss about the process, as a self-reflection of making design decisions from the designers’ end, seeing the tool as a part of the design description.

Scaffolding Generation using a 3D Physarum Polycephalum Simulation

In this demo, we present a novel technique for defining topologically optimal scaffoldings for 3D printed objects using a Monte Carlo algorithm based on the foraging behavior of the Physarum polycephalum slime mold. As a case study, we have created a biologically inspired bicycle helmet using this technique that is designed to be effective in resisting impacts. We have created a prototype of this helmet and propose further studies that measure the effectiveness and validity of the design.

sPrintr: Towards In-Situ Personal Fabrication using a Mobile 3D Printer

We present our early work on sPrintr, a pipeline consisting of a mobile 3D printer and graphical interface to enable in-situ fabrication with consumer-grade hardware and fabrication tools. We prototyped two initial components of that pipeline i) a mobile 3D printer and ii) a user interface that helps users arrange, preview, and plan prints in their environment using a floor plan layout. We identify challenges in the automation of mobile printing systems, on-the-go printing, and human-machine interfaces for in-situ design and fabrication.

Triple Weave with Noise Synthesis

Urumbu: Minimal Machine Building

Computational fabrication has enabled the widespread adoption of rapid-prototyping. There has however been a much higher barrier to entry to make a machine. We investigate rapid-prototyping of rapid-prototyping, so that designing a machine can become as accessible as producing projects on one. We characterize minimum viable components for machine building, including "controllerless" designs that virtualize low-level controls in high-level parallel software, simplified systems for force transmission, and tradeoffs in structural systems. In this demo, a machine controlled entirely by a Python application on a host laptop is presented, with communication between the host and the machine at kHz rate. User interaction is enabled by including polling of input modules in the loop. The machine’s behavior is entirely software-defined within the host application, and new modules can be dynamically plugged in with no reconfiguration on the firmware side.