We propose a method to fabricate objects composed of 3D printed flattened pieces with integrated zipper-like structures. The object is manually assembled into a 3D shape by connecting the zipper components. By employing a zipper design that allows for angle-independent connections between patches, our method enables both the surface and zipper components to be printed in the same orientation, resulting in high-quality reconstruction of the input model with a faster 3D printing process that wastes less material. We implement a fully automated pipeline that takes a 3D model as input, converts it into developable patches, generates the zipper structures, and flattens them for subsequent 3D printing. We demonstrate that our approach significantly reduces the fabrication time and support material consumption. We also present application examples that highlight the versatility of our method.

We propose GadJets, an approach to remotely actuating passive materials and mechanisms using air jets for interactive and shape-changing tangible user interfaces (TUIs). Compared to previous HCI research in remote actuation, air jets offer relatively strong, distant, and safe actuation with simple control. Leveraging these advantages, we can selectively actuate multiple passive materials and mechanisms (or GadJet modules) using only one actuator. We defined a design space to outline the basic architecture and generalizable primitives for air-jet-based TUIs. Also, we exemplified our approach with diverse GadJets modules and proof-of-concept implementation of a computer-controlled air jet system. Finally, we developed a visualization system of the estimated air range based on pre-collected data to support user control. With the vision of deploying multiple passive GadJet modules in an environment fused with the actuated air jets, we demonstrated applications of interactive tabletop objects, an actuated workbench, and an actuated shelf.

Despite the recent trend of computational origami for human-computer interaction (HCI) and digital fabrication, it is still difficult for designers to complete a series of design, simulation, and fabrication of objects leveraging computational origami theory. In this paper, we propose Crane, an integrated origami design platform implemented with Grasshopper. With this platform, users can seamlessly (1) design the 2D and 3D crease pattern, (2) simulate 3D folding transformation from the given crease pattern, (3) inversely find a new pattern under design constraints, (4) thicken the 2D pattern into a 3D volume along with the appropriate hinge structures for different fabrication methods, and (5) optionally connect the resulting design to other Rhinoceros or Grasshopper plugins for post-processes. To help understand how to use our system and demonstrate its feasibility, we showed three examples of origami products designed using our system. We also reported user feedback from the workshop as an evaluation.

We propose Inkjet 4D Print, a self-folding fabrication method of 3D origami tessellations by printing 2D patterns on both sides of a heat-shrinkable base sheet, using a commercialized inkjet ultraviolet (UV) printer. Compared to the previous folding-based 4D printing approach using fused deposition modeling (FDM) 3D printers [An et al. 2018], our method has merits in (1) more than 1200 times higher resolution in terms of the number of self-foldable facets, (2) 2.8 times faster printing speed, and (3) optional full-color decoration. This paper describes the material selection, the folding mechanism, the heating condition, and the printing patterns to self-fold both known and freeform tessellations. We also evaluated the self-folding resolution, the printing and transformation speed, and the shape accuracy of our method. Finally, we demonstrated applications enabled by our self-foldable tessellated objects.

Origami/kirigami robotics are opening a path that leads to lightweight, compact, and expandable robots. However, it is generally challenging to design agile motions for origami/kirigami robots due to their size and the intrinsic limitation of the materials. In this paper, we propose to use the bistability of the waterbomb base structure to generate the swift motion of the robots. We evaluate the bistability of the waterbomb-based structure and build origami jumpers with different configurations of the body to help analyze the behavior of the waterbomb base bistable structure. The jumper is actuated by a phase change liquid pouch actuator. Our jumper is lightweight (0.3 g), flattenable, and able to jump to more than 12 times of its diameter and 112 times of its height.

Flower jellies, a delicate dessert in which a flower-shaped jelly floats inside another clear jelly, fascinate people with both their beauty and elaborate construction. In efforts to simplify the challenging fabrication and enrich the design space of this dessert, we present Flower Jelly Printer: a printing device and design software for digitally fabricating flower jellies. Our design software lets users play with parameters and preview the resulting forms until achieving their desired shapes. We also developed slit injection printing that directly injects colored jelly into a base jelly, and shared several design examples to show the breadth of design possibilities. Finally, the user study with novice and experienced users demonstrates that our system benefits creators of all experience levels by iterative design and precise fabrication. We hope to enable more people to design and create their own flower jellies while expanding access and the design space for digitally fabricated foods.

Kirigami Haptic Swatches demonstrate how kirigami and origami based structures enable sophisticated haptic feedback through simple cut-and-fold fabrication techniques. We leverage four types of geometric patterns: rotational erection system (RES), split-fold waterbomb (SFWB), the overlaid structure of SFWB and RES (SFWB+RES), and cylindrical origami, to render different sets of haptic feedback (i.e. linear, bistable, bouncing snap-through, and rotational force behaviors, respectively). In each structure, not only the form factor but also the force feedback properties can be tuned through geometric parameters. We experimentally analyzed and modeled the structures, and implemented software to automatically generate 2D patterns for desired haptic properties. We also demonstrate five example applications including an assistive custom keyboard, rotational switch, multi-sensory toy, task checklist, and phone accessories. We believe the Kirigami Haptic Swatches helps tinkerers, designers, and even researchers to create interactions that enrich our haptic experience.

Despite the recent growth in popularity of personal mobility devices (e.g., e-scooters and e-skateboards), they still suffer from limited safety and narrow design form factors, due to their rigid structures. On the other hand, inflatable interfaces studied in human-computer interaction can achieve large volume change by simple inflation/deflation. Inflatable structure also offers soft and safe interaction owing to material compliance and diverse fabrication methods that lead to a wide range of forms and aesthetics. In this paper, we propose poimo, a new family of POrtable and Inflatable MObility devices, which consists of inflatable frames, inflatable wheels, and inflatable steering mechanisms made of a mass-manufacturable material called drop-stitch fabric. First, we defined the basic material properties of a drop-stitch inflatable structure that is sufficiently strong to carry a person while simultaneously allowing soft deformation and deflation for storage and portability. We then implemented an interactive design system that can scan the user's desired riding posture to generate a customized personal mobility device and can add the user's shape and color preferences. To demonstrate the custom-design capability and mobility, we designed several 3D models using our system and built physical samples for two basic templates: a motorcycle and a wheelchair. Finally, we conducted an online user study to examine the usability of the design system and share lessons learned for further improvements in the design and fabrication of poimo.

Despite recent advancements in 3D printing technology, which allows users to rapidly produce 3D objects, printing tall and/or large objects still consumes more time and large amount of support material. In order to address these problems, we propose Pop-up Print, a method to 3D print an object in a compact "folded" state and then unfold it after printing to achieve the final artifact. Using this method, we can reduce the object's print height and volume, which directly affects the printing time and support material consumption. In addition, thanks to the reversibility of folding/unfolding, we can reversibly minimize the printed object's volume when unused for storage or transportation, and expand it only in use. To achieve Pop-up Print, we first conducted an experiment using selected printed sample objects with several parameters, in order to determine suitable crease patterns that make both the unfolded and folded state mechanically stable. Based on this result, we developed an interactive design tool to convert 3D models - such as a Stanford Bunny or a Huffman's cone - to the folded shape. Our design tool allows users to decide non-intuitive parameters that may affect the form's mechanical stability, while maintaining both functional crease patterns and the object's original form factor. Finally, we demonstrate the feasibility of our method through several examples of folded objects.

Living things in nature have long been utilizing the ability to "heal" their wounds on the soft bodies to survive in the outer environment. In order to impart this self-healing property to our daily life interface, we propose Self-healing UI, a soft-bodied interface that can intrinsically self-heal damages without external stimuli or glue. The key material to achieving Self-healing UI is MWCNTs-PBS, a composite material of a self-healing polymer polyborosiloxane (PBS) and a filler material multi-walled carbon nanotubes (MWCNTs), which retains mechanical and electrical self-healability. We developed a hybrid model that combines PBS, MWCNTs-PBS, and other common soft materials including fabric and silicone to build interface devices with self-healing, sensing, and actuation capability. These devices were implemented by layer-by-layer stacking fabrication without glue or any post-processing, by leveraging the materials' inherent self-healing property between two layers. We then demonstrated sensing primitives and interactive applications that extend the design space of shape-changing interfaces with their ability to transform, conform, reconfigure, heal, and fuse, which we believe can enrich the toolbox of human-computer interaction (HCI).

The integrated fabrication of body structures, actuators, sensors, and electronic circuits into one robot system is an open problem in robotics. Simple and rapid construction of electric actuators in the body through existing approaches is difficult. We take advantage of the liquid-to-gas phase change, and propose an electric phase-change actuator comprising a printable fluidic actuator controlled by an inkjet printed electric heater. The actuator can easily be integrated with origami robots. We theoretically analyze the dynamics of electro-fluidic conversion in the actuator and compare it with actual measurement data. The proposed actuator is verified in real examples of a shape-shifting origami structure and a robot gripper with a printed touch sensor.

In this paper, we propose a passive and contactless epidermal pressure sensor patch printed on a paper substrate with silver nano-particle ink. This disposable patch can be used to measure the pressure between the clothes and the human body. Different from the conventional pressure sensors, the pressure can be measured wirelessly without disturbing the motion of the users. The sensor circuit pattern is printed by a conductive inkjet printer and the sensor's pressure value is detected by a reader coil through the change of the capacitance of an LC resonant circuit. We propose a sensor design method that minimizes the effect of the human body. We demonstrate our sensor patch by measuring the pressure exerted by compression garments whose pressure distribution is important for the wearer's health.

Recent advances in materials science have resulted in a range of commercially viable and easy-to-use conductive inks which novices, hobbyists, educators, students and researchers are now using to design and build interactive circuits quickly. Despite the ease with which practitioners can construct working circuits, one of the major limitations of designing circuits on-the-fly is the difficulty of detecting and understanding errors in prototype circuits. As well as short- and open-circuits, which often prevent a circuit from working at all, more subtle issues like high resistance traces can result in poor performance. Many users can't readily work out how to successfully modify their circuits, and they often don't have the tools or expertise to measure the relevant circuit parameters. In this paper we present ConductAR, a tool which can recognize and analyze hand-drawn, printed and hybrid conductive ink patterns. An on-screen augmented reality style interaction helps users to understand and enhance circuit operation. A key element of ConductAR is its ability to calculate the resistance of a circuit using a camera attached to an off-the-shelf PC or tablet. Our sparse coding technique is fast enough to support rapid iterative prototyping on real circuits using a conductive ink marker and/or eraser as shown in Figure 1. The system thereby enhances the feasibility of circuit prototyping with conductive ink.

Instant Inkjet Circuits by silver nano-particle ink realized home-brew electric circuit fabrication. However, current method can support only single-layered patterns, and conventional inter-layer connection methods are not suitable. In this paper, we will evaluate various easy-to-use inter-layer connection methods by making via holes, especially the ones made by different drilling mechanisms. We show that the felting needle is the best candidate as it can establish good conductivity immediately after nano-particle ink is printed into the hole, without using any curing process.