DropPop: Designing Drop-to-Deploy Mechanisms with Bistable Scissors StructuresDeployable structures often rely on complex deployment mechanisms such as external pneumatic pumps, electric motors, or manual assembly. These conventional methods, which are intended for applications in shape morphing architectures, robotics, and product design, can be bulky and unwieldy for everyday interaction and daily use. We introduce a new class of deployable structures that harness the locomotion of a single bistable cap to drive the expansion of a scissor-like mechanism. Such structures can be rapidly deployed (0.2-0.7s) upon a small trigger, and stabilize themselves requiring no sustained energy input. We explore various input modalities for deployment such as hand dropping, and drone deployment, and showcase demo applications. Additionally, we provide a computational design tool for customizing shape primitives with physics simulation and offer design guidelines for fabrication.2025YFYibo Fu et al.Shape-Changing Interfaces & Soft Robotic MaterialsShape-Changing Materials & 4D PrintingUIST
Wearable Material Properties: Passive Wearable Microstructures as Adaptable Interfaces for the Physical EnvironmentUsers interact with static objects daily, but their preferences and needs may vary. Making the objects dynamic or adaptable requires updating all objects. Instead, we propose a novel wearable interface that empowers users to adjust perceived material properties. To explore such wearable interfaces, we design unit cell structures that can be tiled to create surfaces with switchable properties. Each unit can be switched between two states while worn, through an integrated bistable spring and tendon-driven trigger mechanism. Our switchable properties include stiffness, height, shape, texture, and their combinations. Our wearable material interfaces are passive, 3D printed, and personalizable. We present a design tool to support users in designing their customized wearable material properties. We demonstrate several example prototypes, e.g., a sleeve allowing users to adapt to how different surfaces feel, a shoe sole for users walking on different ground conditions, a prototype supporting both pillow and protective helmet properties, or a collar that can be transformed into a neck pillow with variable support.2025YLYuyu Lin et al.Carnegie Mellon UniversityHaptic WearablesShape-Changing Interfaces & Soft Robotic MaterialsCustomizable & Personalized ObjectsCHI
ElectriPop: Low-Cost, Shape-Changing Displays Using Electrostatically Inflated Mylar SheetsWe describe how sheets of metalized mylar can be cut and then “inflated” into complex 3D forms with electrostatic charge for use in digitally-controlled, shape-changing displays. This is achieved by placing and nesting various cuts, slits and holes such that mylar elements repel from one another to reach an equilibrium state. Importantly, our technique is compatible with industrial and hobbyist cutting processes, from die and laser cutting to handheld exacto-knives and scissors. Given that mylar film costs <$1 per m^2, we can create self-actuating 3D objects for just a few cents, opening new uses in low-cost consumer goods. We describe a design vocabulary, interactive simulation tool, fabrication guide, and proof-of-concept electrostatic actuation hardware. We detail our technique's performance metrics along with qualitative feedback from a design study. We present numerous examples generated using our pipeline to illustrate the rich creative potential of our method.2022CFCathy Mengying Fang et al.Carnegie Mellon UniversityShape-Changing Interfaces & Soft Robotic MaterialsShape-Changing Materials & 4D PrintingCHI
PneuMesh: Pneumatic-driven Truss-based Shape Changing SystemFrom cross-sea bridges to large-scale installations, truss structures have been known for their structural stability and shape complexity. In addition to the advantages of static trusses, truss structure has a large degree of freedom to change shape when equipped with rotatable joints and retractable beams. However, it is difficult to design a complex motion and build a control system for large numbers of trusses. In this paper, we present PneuMesh, a novel truss-based shape-changing system that is easy to design and build but still able to achieve a range of tasks. PneuMesh accomplishes this by introducing an air channel connection strategy and reconfigurable constraint design that drastically decreases the number of control units without losing the complexity of shape-changing. We develop a design tool with real-time simulation to assist users in designing the shape and motion of truss-based shape-changing robots and devices. A design session with 7 participants demonstrates that PneuMesh empowers users to design and build truss structures with a wide range of shapes and various functional motions.2022JGJianzhe Gu et al.Carnegie Mellon UniversityShape-Changing Interfaces & Soft Robotic MaterialsCHI
FlexTruss: A Computational Threading Method for Multi-material, Multi-form and Multi-use Prototyping3D printing, as a rapid prototyping technique, usually fabricates objects that are difficult to modify physically. This paper presents FlexTruss, a design and construction pipeline based on the assembly of modularized truss-shaped objects fabricated with conventional 3D printers and assembled by threading. To create an end-to-end system, a parametric design tool with an optimal Euler path calculation method is developed, which can support both inverse and forward design workflow and multi-material construction of modular parts. In addition, the assembly of truss modules by threading is evaluated with a series of application cases to demonstrate the affordance of FlexTruss. We believe that FlexTruss extends the design space of 3D printing beyond typically hard and fixed forms, and it will provide new capabilities for designers and researchers to explore the use of such flexible truss structures in human-object interaction.2021LSLingyun Sun et al.Zhejiang UniversityDesktop 3D Printing & Personal FabricationLaser Cutting & Digital FabricationCHI
SimuLearn: Fast and Accurate Simulator to Support Morphing Materials Design and WorkflowsMorphing materials allow us to create new modalities of interaction and fabrication by leveraging the materials’ dynamic behaviors. Yet, despite the ongoing rapid growth of computational tools within this realm, current developments are bottlenecked by the lack of an effective simulation method. As a result, existing design tools must trade-off between speed and accuracy to support a real-time interactive design scenario. In response, we introduce SimuLearn, a data-driven method that combines finite element analysis and machine learning to create real-time (0.61 seconds) and truthful (97% accuracy) morphing material simulators. We use mesh-like 4D printed structures to contextualize this method and prototype design tools to exemplify the design workflows and spaces enabled by a fast and accurate simulation method. Situating this work among existing literature, we believe SimuLearn is a timely addition to the HCI CAD toolbox that can enable the proliferation of morphing materials.2020HYHumphrey Yang et al.Shape-Changing Interfaces & Soft Robotic MaterialsShape-Changing Materials & 4D PrintingComputational Methods in HCIUIST
E-seed: Shape-Changing Interfaces that Self DrillAs sensors and interactive devices become ubiquitous and transition outdoors and into the wild, we are met with the challenge of mass deployment and actuation. We present Eseed, a biomimetic platform that consumes little power to deploy, harvests energy from nature to install, and functions autonomously in the field. Each seed can individually selfdrill into a substrate by harvesting moisture fluctuations in its ambient environment. As such, E-seed acts as a shapechanging interface to autonomously embed functional devices and interfaces into the soil, with the potential of aerial deployment in hard-to-reach locations. Our system is constructed primarily from wood veneer, making it lightweight, inexpensive, and biodegradable. In this paper, we detail our fabrication process and showcase demos that leverage the E-seed platform as a self-drilling interface. We envision that possible applications include soil sensors, sampling, and environmental monitoring for agriculture and reforestation.2020DLDanli Luo et al.Shape-Changing Interfaces & Soft Robotic MaterialsSustainable HCIEcological Design & Green ComputingUIST
Geodesy: Self-rising 2.5D Tiles by Printing along 2D Geodesic Closed PathThermoplastic and Fused Deposition Modeling (FDM) based 4D printing are rapidly expanding to allow for space- and material-saving 2D printed sheets morphing into 3D shapes when heated. However, to our knowledge, all the known examples are either origami-based models with obvious folding hinges, or beam-based models with holes on the morphing surfaces. Morphing continuous double-curvature surfaces remains a challenge, both in terms of a tailored toolpath-planning strategy and a computational model that simulates it. Additionally, neither approach takes surface texture as a design parameter in its computational pipeline. To extend the design space of FDM-based 4D printing, in Geodesy, we focus on the morphing of continuous double-curvature surfaces or surface textures. We suggest a unique tool path - printing thermoplastics along 2D closed geodesic paths to form a surface with one raised continuous double-curvature tiles when exposed to heat. The design space is further extended to more complex geometries composed of a network of rising tiles (i.e., surface textures). Both design components and the computational pipeline are explained in the paper, followed by several printed geometric examples.2019JGJianzhe Gu et al.Carnegie Mellon UniversityShape-Changing Interfaces & Soft Robotic MaterialsDesktop 3D Printing & Personal FabricationCHI
Self-healing UI: Mechanically and Electrically Self-healing Materials for Sensing and Actuation InterfacesLiving 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 retain 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 soft interface with their ability to transform, conform, reconfigure, heal, and fuse, which we believe can enrich the toolbox of human-computer interaction (HCI).2019KNKoya Narumi et al.Haptic WearablesShape-Changing Interfaces & Soft Robotic MaterialsShape-Changing Materials & 4D PrintingUIST
Thermorph: Democratizing 4D Printing of Self-Folding Materials and InterfacesWe develop a novel method printing complex self-folding geometries. We demonstrated that with a desktop fused deposition modeling (FDM) 3D printer, off-the-shelf printing filaments and a design editor, we can print flat thermoplastic composites and trigger them to self-fold into 3D with arbitrary bending angles. This is a suitable technique, called Thermorph, to prototype hollow and foldable 3D shapes without losing key features. We describe a new curved folding origami design algorithm, compiling given arbitrary 3D models to 2D unfolded models in G-Code for FDM printers. To demonstrate the Thermorph platform, we designed and printed complex self-folding geometries (up to 70 faces), including 15 self-curved geometric primitives and 4 self-curved applications, such as chairs, the simplified Stanford Bunny and flowers. Compared to the standard 3D printing, our method saves up to 60% - 87% of the printing time for all shapes chosen.2018BAByoungkwon An et al.Carnegie Mellon University, Duke UniversityShape-Changing Materials & 4D PrintingCHI
Printed Paper Actuator: A Low-cost Reversible Actuation and Sensing Method for Shape Changing InterfacesWe present a printed paper actuator as a low cost, reversible and electrical actuation and sensing method. This is a novel but easily accessible enabling technology that expands upon the library of actuation-sensing materials in HCI. By integrating three physical phenomena, including the bilayer bending actuation, the shape memory effect of the thermoplastic and the current-driven joule heating via conductive printing filament, we developed the actuator by simply printing a single layer conductive Polylactide (PLA) on a piece of copy paper via a desktop fused deposition modeling (FDM) 3D printer. This paper describes the fabrication process, the material mechanism, and the transformation primitives, followed by the electronic sensing and control methods. A software tool that assists the design, simulation and printing toolpath generation is introduced. Finally, we explored applications under four contexts: robotics, interactive art, entertainment and home environment.2018GWGuanyun Wang et al.Carnegie Mellon UniversityShape-Changing Interfaces & Soft Robotic MaterialsDesktop 3D Printing & Personal FabricationShape-Changing Materials & 4D PrintingCHI
4DMesh: 4D Printing Morphing Non-Developable Mesh SurfacesWe present 4DMesh, a method of combining shrinking and bending thermoplastic actuators with customized geometric algorithms to 4D print and morph centimeter- to meter-sized functional non-developable surfaces. We will share two end-to-end inverse design algorithms. With our tools, users can input CAD models of target surfaces and produce respective printable files. The flat sheet printed can morph into target surfaces when triggered by heat. This system saves shipping and packaging costs, in addition to enabling customizability for the design of relatively large non-developable structures. We designed a few functional artifacts to leverage the advantage of non-developable surfaces for their unique functionalities in aesthetics, mechanical strength, geometric ergonomics and other functionalities. In addition, we demonstrated how this technique can potentially be adapted to customize molds for industrial parts (e.g., car, boat, etc.) in the future.2018GWGuanyun Wang et al.Shape-Changing Interfaces & Soft Robotic MaterialsShape-Changing Materials & 4D PrintingUIST