Shape-Changing Devices

From CS294-84 Spring 2013
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Valkyrie Arline Savage, PhD - 3/10/2013 11:25:59

Shape-changing devices in general are totally cool. The shape-changing interfaces paper gives an interesting hat tip to previous work based in mechanical interactions: a mechanical alphabet made up of “vowels” (lever, wedge, screw, pulley, winch) and “consonants” by which one can construct any possible machine. From there it goes on to describe what such an alphabet might look like for shape-changing interfaces. It’s not clear that they really do a good job of this, but it’s an important idea. I thought their list of relevant properties for shape-changing materials was quite exhaustive and interesting. I haven’t yet come up with something that I wish they’d included... Their prototypes were also interesting, although a bit silly. They served as a good demonstration of the capabilities of shape-changing materials to suggest particular affordances and act in different ways on the environment.

Harrison’s paper about actuatable acrylic + latex buttons was pretty awesome. My main gripe with it was that they tried to argue that there is something to be said about “approaching significance” with their measured values between the flat touchscreen and their new interfaces as far as time measurements go. Seems to me that that is unequivocally not true. Significance is binary. Anyway, the idea is sound, and being able to use a laser cutter to quickly prototype novel interfaces that work is pretty great. It’s interesting to think about how capacitance might be integrated into such prototypes as these: since they are arguing that such tactile interfaces could be important in a mobile context, it’s important to consider that. Obviously the buttons would have to be smaller in area, since the size of z-axis displacement of the buttons they demonstrated with seemed to be greater than the thickness of a mobile phone.  :)

Jamming user interfaces: I’m not totally clear on some aspects of the history of this. The authors state that particle jamming has been used by folks in other fields for a variety of purposes, so I don’t quite get what their contributions are beyond current uses in those other fields. That aside, jamming is a cool phenomenon. Their observations related to index matching are fascinating. One criticism : no user study! They didn’t even really give convincing numbers on especially the capacitive touch sensing. They mentioned that sensing with capacitive grids is hard, especially when a person is touching the interface, so I would really have liked to see some kind of test where they, uh, tried that.

elliot nahman - 3/18/2013 21:26:09

Shape changing devices This paper examines the potential around shape changing devices. It provides a brief survey of different materials which have shape changing capabilities and provides a set of criteria by which to categorize shape changing materials. The paper then goes on to build three device prototypes using one type of shape changing material.

The authors explain the following properties of shape changing materials:

  • Deformation strength and power requirements: Inversely proportional and limit size/mobility
  • Speed and resolution: response curve and ease of control
  • Number of active memory shapes
  • Transition Quality: really asking if the material transitions with enough force to apply external forces on other actuators.
  • Trainability: can the material be given new shapes after being cast
  • Reversibility: recover from shape changes and decay?
  • Input stimulus: type of stimulus the material responds to
  • Bi-Directionality: basically I/O coincidence. Can it be used as input and output through physical manipulations
  • Environment compatibility: does it need a special environment to operate; does it operate only under specific conditions
  • Consistency: solid or liquid

Overall, this seems like a good list of qualities to examine when thinking about shape changing materials. However, I find it odd that they propose this list, yet do not discuss all elements of the list in the comparative table of shape changing materials. Nor do the dive into all these elements when discussing the material of choice, shape memory alloys. They also categorize materials very generally instead of going into more specific metrics. For instance, Displacement, they say Small and Large, but what does that actually mean? They never say Large = transformations that are > x times the material height, or some quantifiable number like that.

The authors also discuss three types of transformations:

  • Topological: change shape
  • Textural: change in surface; shape remains the same
  • Permeable: change porosity/transparency

When it comes to their device tests, that is when the lack of information about the above property list really shows. Surflex is constructed out of foam with embedded SMAs to control its shape. It creates topological changes going from flat, to U-shaped. However the authors test no concrete application. They propose two possibilities, but their current demo does not seem able to yet support their propositions. Furthermore, they show images of Surflex changing shapes, but make no mention of the characteristics of that transformation. How long did it take, 5 sec or 5 min? How much heat is required to actually actuate the response? Is it cool enough to touch? Fire danger?

The next device they design actually has an application. It is SpeakCup, a disk which the user physically manipulates in order to control whether it is an input or output device. That I/O coincidence is quite a compelling feature. Although a much more compelling and though out design, like Surflex, SpeakCup still does not go into any technical specifics about operation.

Sprout IO and Shutters tests a textural change rather than a topological change. Here, they propose a system which actuates several smaller features to change the appearance of the device. They propose Shutters as a possible application of shading devices for buildings. This really makes me wonder about the durability of their technology and its ability to operate under extreme conditions, wind, rain, snow, temperature changes. Given it is a material that responds to temperature changes, at what temperature does that occur? What happens when it is exposed to and absorbing sunlight all day long? Or is faced with a near freezing wind? Again, not enough specifics of the technology are given to actually make any assessment as to whether or not their idea is at all viable and they do not testing to suggest that it might be.

Jamming User Interfaces: The authors explore particle “jamming” user interfaces. Jamming is a granular medium which can be shaped by the user or pneumatic system. The material is:

  • variable stiffness
  • rigidity of form
  • user defined

4 elements of a jamming system:

  • jamming material and housing assembly
  • vacuum source or pump
  • pressure control valve
  • pressure sensor

They explored two types of sensing:

  • Optical

--IR diffusion --Claim FTIR could be explored….how so? Wouldn’t surface irregularities allow IR to escape?

  • Capacitance

--distance --stretch and bend --shape/vol --multitouch


  • tunable clay:

--3d modeling design tool --pot to control stiffness ---I assume this an all or nothing system. There is no way to make one section stiff while still working on another. --how easy is it to mold geometric shapes rather than just organic shapes? --ability to use tools? --rate of slumping when tune stiffness down?

  • Transparent Haptic lens

--haptic feedback through stiffness --like TeslaTouch, provides haptic “active” haptic feedback where the user must squeeze the device to notice the change. --Can it actively change shape in response to feedback or just stiffness? --need a more concrete application

  • Tablet jamming:

--mounts on the back of a tablet --input device “with gestures” What are they? --scenario: kneading to scroll. When user reaches the extents, material stiffens. ---Does the whole display turn stiff or just the side that they were scrolling on? How does one reset the display after they’ve knead-scrolled and then changed to a new page or application? ---how long would such a transformation take?

  • Shape phone

--malleable phone that could be a capacitance sensor --their prototype has not electronics in it. How is it a phone? What troubles/limitations would they run into with components embedded in their system? Antennae, LCD screen, speakers, etc --seems more like a plugin input device for a phone but they don't explicitly say that is what it could be used for.

In general, this seems like a really half baked system. There is some neat potential, but they don't really do any analysis as to the usability of their devices. Nor do they provide much in the way of metrics for judging their material. I would like to see cataloged in the properties listed in Shape Changing Devices. Speed and resolution, transition quality, time, reversibility, bi-directionality, etc. Also, like with the next paper, can they use the pressure sensor to detect input? With the diffuse IR, they don't discuss the trouble of detecting a touch from a hover; is this a problem?

Dynamic Changeable Physical Buttons: This paper explores creating dynamic buttons using pneumatics. These buttons can be overlaid on a display and multitouch capabilities through rear diffuse IR. The system can also use pressure to distinguish button pushes from hovering. Buttons can be positive or negative The authors conducted a user test comparing positive buttons, negative buttons, physical buttons, and a flat touch screen and found that their positive button system outperformed even the physical buttons.

This study is quite thorough and explores the system in depth. An obvious limitation, which they mention, is that one is limited in the button configuration of a particular display; you cannot dynamically rearrange buttons on the fly, but you can reassign them. Other than the fact that you can make active buttons appear and then disappear when deactivated, what is the real advantage over static physical buttons? It is a huge tradeoff between size and complexity for limited configurability. Moreover, I wonder what these buttons really feel like? I image they are squishy and the real depression point at which it activates a click is not as apparent as a real button.

Ben Zhang, PhD - 3/19/2013 0:07:19

  • Changeable Buttons(Harrison)

The benefit of physical button is of no doubt, but integrating them into dynamic changeable screen is a huge problem. This paper investigate the possibility of using pneumatic actuation, with an intelligent use of latex to create various ways of forming physical buttons. The system can also incorporate other techniques such as vision-based multi-touching, and barometer sensing to enhance user interaction. Three example applications (automobiles, existing multi-touch, kiosks/ATMs) are presented and followed by a user study which demonstrates the benefit of having such physical buttons.

The overall paper is nice to read and follow, and various design space with nice illustrating graphs make it easy to understand. I personally like it when authors identifies their limitations in this paper; such discussion give clear guideline about when this system may perform good, and when not. The major concern that I have during reading is exactly what the author has pointed out -- "their tactile features are statically arranged". You have to pre-print a skeleton and use it. It might actually be possible to design complex schemes so that even if the buttons are not per-pixel, but can be arrange in an illusion of per pixel, which might still impose constraints on the display design, but has provided more flexibility. On the other side, the pneumatic solution seems pretty difficult to set up and subject to leakage. Lacking experience of dealing with them, I can hardly judge. But such problem is also reported in the paper.

Though I am more impressed by a recent startup called tactus (not sure if they have relation with this paper), this early approach demonstrates many possibilities of forming buttons in different styles, providing dynamics.

  • Shape-changing interfaces (Coelho)

This paper first presents a survey of recent development of shape-changing materials, which functions as the enablers for potential advanced interactions. After defining several key properties, four projects are discussed about their ideas, engineering work, and their different transforming characteristics.

The survey in this paper opens up a wide variety of choices when designing shape-changing objects. Not only a pure list of possibilities is offered, but rather the properties (such as deformation strength, power requirements, possible shape numbers, transition quality, trainability, reversibility, etc.) are discussed. This is of great benefit to readers. Then the paper introduces three types of surface transformation - topological, textural, permeable. And accordingly, they have projects for each of them. Suflex and SpeakCup are topological changes. Sprout I/O is texture based, and shutters is utilizing dynamic permeability. For these projects, some also have involved ways of sensing for interaction, rather than just a changing in shape. This brought up the discussion of ways that can enhance interaction by the shape transformation. You may encode dynamic functions into different forms, or as physical representation of dynamic data, or maybe guide the ways of interaction. In short, this paper serves more as a portal for readers to capture the recent development in material science that can be considered in an HCI context.

  • Jamming User Interfaces (Follmer)

This paper focuses the scope to discussing ways to design a particle jamming system. As a simple, effective method to create shape changing interface, the ability to control stiffness programmatically also makes it suitable for interaction system.

In addition to the jamming shape changing, they also present two novel ways of sensing (I personally find the index-matching solution very clever). The prototype applications are also interesting. Tunable clay combines projection and sensing to augment the modeling process. Transparent Haptic Lens enables user to feel the stiffness for different contents.

ShapePhone might be the most interesting one, since this can provide a natural solution for user to interact with multiple objects around -- they don't need to choose the right controller any more. A single shape changeable device would suffice and what the user needs to do is so intuitive -- form the phone into a desired shape. However, there is few discussion in the paper about how displays, other sensing can be combined in this promising application.

David Burnett - 3/19/2013 0:17:18


Sean Chen - 3/19/2013 1:59:36

Shape-changing interfaces

This paper talks about the foundation for the shape-changing surface design. It introduce various types of materials and the properties and limitations of them, providing a nice intro level knowledge for the novice readers.

It also explains some terms used in material science, different types of transformations, and example researches.

In previous readings, researches such as SLAP provide a fixed haptic feedback to allow users interact with familiar inputs without the need of looking at it. Shape-changing interfaces also provide tangible feedbacks, but it seems like they are used in a different scenario. Since their shapes can change dynamically, they can be used to inform the users the various stage or ways to interact with the system, rather than providing a familiar haptic feedback.

Providing Dynamically Changeable Physical Buttons on a Visual Display

This paper describes a new input method which creates dynamic physical buttons using pneumatic actuation. The buttons can be designed so that positive and negative states can display different shapes. The buttons can sense input by either Diffused Illumination Multitouch sensing or by air pressure.

I like the novelty of this method. And they did a good job on exploring various possible alternatives when building the input.

The negative state doesn't have as much haptic feedback, can not sense the pressing pressure, and doesn't have a good user feedback.

I think about the current ATM input, which has buttons on the sides of the display, and compare it with this design. It seems like this design can provide a little richer experience. However, it doesn't take durability into account. A latex surface can be much more easily broken. And holes in on button might mean the need of the replacement for the whole surface. And the cost of it is apparently higher than touch screen or buttons.

For its user study, it still din't make the texture of the 4 approaches identical. To compare physical buttons versus positive ones, I would challenge that perhaps users like the rounded edge and elastic feel of the positive buttons, which can also be implemented on physical buttons. Overall, I think the author didn't come up with use cases that are compelling enough.

Jamming User Interfaces

This paper describe a method called jamming, which allows the material to switch between fluid and solid-like states. This method in combination of the shape sensing technique provide novel interactions and increased expressiveness.

This technique has the capability to control material stiffness, which can represent states in the user interface. This paper covers a wild range of domains, and did a thorough job on the related works and explanation of the design. The pneumatic and hydraulic jamming each has their pros and cons.

The interface only works from passive actuation. Therefore, it can't decide what shape to be changed on its own. I think this research fits into one of those categories of "here's a novel method and some interesting possible use cases, but I don't know which existing design it can replace." Since there's no solid applications, there's no user study as well.

Joey Greenspun - 3/19/2013 8:43:30

Shape-Changing Interfaces:

This article is a general overview on the design of shape-changing surfaces as they pertain to the field of human computer interaction. They mention both general designs of shape changing materials as well as four designs that implement the materials: Surflex, SpeakCup, Sprout I/O, and Shutters. In general, all of these devices didn’t really scream human computer interaction to me. When I think about shape change as it relates to how we interact with our devices, I first think computer keyboards that change shape to give additional tactile feedback or to change their layout based on the application. The four mentioned devices were very far from this functionality. Surflex, was interesting and with some more refining, I think it could actually be beneficial in visualizing 3d models. However, it is too low resolution at this stage to be useful in my opinion. I hated SpeakCup. I don’t think there is anything interesting about recording and replaying sound on a device. However, I gave them the benefit of the doubt and thought, well at least they can map the two positions to other more useful actions. But, they kept harping on how their device was being intuitive in that, it makes sense that when it is concave it records and convex it plays. Sprout I/O was probably my favorite of the mentioned applications. It at first seemed a bit useless, however the one application that really got me was the artificial grass guiding crowds to their destination, or towards an exit. That would be very cool and is essentially giving intelligence to something we don’t really think about interacting with. Additionally I cracked up when they mentioned putting these on robots to allow them to sense fine subtleties of touch and “respond with goose bumps to create tighter emotional bonds with their owners.” Shutters was a decent project. I don’t really see it as HCI just because it’s more just adapting to its environment. But there is definitely a benefit in that. Having smart shades is both desirable and interesting. The thought of using them as a display is intriguing.

Jamming User Interfaces:

This paper focuses on the idea of jamming, i.e. programmatically controlling material stiffness, as it pertains to the field of HCI, specifically its usability in tabletops and tablets. This paper reviews a variety of jamming techniques such as Pneumatics for Portability and Hydraulic Jamming. The researchers built four prototypes to study the various means of varying material stiffness and use it as an input device. Tunable Clay is a device that users use to sculpt and create a 3D model using a material whose stiffness can be controlled programmatically. This, although it seems like a very niche product, would be incredible for some artists. The ability to increase the stiffness of a material when desiring to do fine tuning of the sculpture, seems highly desirable. However, I don’t see how this could be adapted to be used as a more general input device. Transparent Haptic lens is a device that sits over a smart tabletop and when pressed, gives a variable resistance based on what image is under the lens at that time. This is a similar sort of device to slap widgets. I don’t see how much this really adds to the user experience. It seems a bit gimmicky. Behind-the-table Jamming is by far my favorite of the four devices. It is functionalizing the back of a tablet with a smart material that is malleable and can be used to input various signals to a tablet. Being able to control your device with otherwise unused fingers that are just being used to hold the device, is a very interesting and appealing idea. ShapePhone is a silicone skin that can be stretched and molded into various shapes and then locked into said shape by flipping a switch. I don’t see the need to be able to stretch a watch shaped device into a remote control or phone shaped device. This seems like a bit of a stretch from anything that could be useful in practice. The technology seems potentially useful, but the application of being able to turn your watch into a tv remote is not.

Providing Dynamically Changeable Physical Buttons:

These researchers are exploring the design space between a purely physical keyboard and a touchscreen. They eventually create a device that very nearly matches the user experience found using physical buttons. I really enjoyed how the researched clearly laid out their five goals at the start of the paper. It was a nice framework around which to build our understanding of what they were doing and where they were trying to go with it. Additionally, I thought the general idea is exactly what needs to be done in terms of enhancing touchscreens. They are incredible devices that lack any useful haptic feedback. So, if there is a way we can fill that hole and combine the two, it would revolutionize how we use out touchscreens. One of their goals that I really thought was important was the third one, i.e. being able to display graphics without occlusion from hands or other elements. I think an overhead projection system is the wrong approach for a variety of reasons, and I’m glad the researchers agree. So although I was very excited about this product when I first started reading, I very quickly realized that it wasn’t as versatile as I thought or hoped. The button shapes and locations are not software defined. They are part of a pad and backing that are physical elements of the system. So, although they can be programmatically raised into and out of the usable surface, it will always be the same buttons that are being displayed in the same locations. So I suppose this is certainly a step forward, but it is by no means where the innovation should stop.