Mobile video calls are widely used to share information about real-world objects and environments with remote collaborators. While these calls provide valuable visual context in real time, the experience of interacting with people and moving around a space is significantly reduced when compared to co-located conversations. Recent work has demonstrated the potential of Mobile Augmented Reality applications to enable more spatial forms of collaboration across distance. To better understand the dynamics of mobile AR collaboration and how this medium compares against the status quo, we conducted a comparative structured observation study to analyze people’s perception of space and interaction with remote collaborators across mobile video calls and AR-based calls. Fourteen pairs of participants completed a spatial collaboration task using each medium. Through a mixed-methods analysis of session videos, transcripts, motion logs, post-task exercises, and interviews, we highlight how the choice of medium influences the roles and responsibilities that collaborators take on and the construction of a shared language for coordination. We discuss the importance of spatial reasoning with one’s body, how video calls help participants “be on the same page” more directly, and how AR calls enable both onsite and remote collaborators to engage with the space and each other in ways that resemble in-person interaction. Our study offers a nuanced view of the benefits and limitations of both mediums, and we conclude with a discussion of design implications for future systems that integrate mobile video and AR to better support spatial collaboration in its many forms.

The term ecological validity is widely used across IEEE publications, but its definition and application remain inconsistent and ambiguous. This paper explores how conflicting definitions of ecological validity lead to confusion about experimental conditions and data interpretation. Because the term ecological validity conflates methods with outcomes and presumes that realism creates validity, we argue against its continued use as a separate term. Instead, we recommend using external validity and mundane realism. We believe this change would increase rigor in scientific communications, eliminate ambiguities, and open a transdisciplinary dialogue.

In-person human interaction relies on our spatial perception of each other and our surroundings. Current remote communication tools partially address each of these aspects. Video calls convey real user representations but without spatial interactions. Augmented and Virtual Reality (AR/VR) experiences are immersive and spatial but often use virtual environments and characters instead of real-life representations. Bridging these gaps, we introduce DualStream, a system for synchronous mobile AR remote communication that captures, streams, and displays spatial representations of users and their surroundings. DualStream supports transitions between user and environment representations with different levels of visuospatial fidelity, as well as the creation of persistent shared spaces using environment snapshots. We demonstrate how DualStream can enable spatial communication in real-world contexts, and support the creation of blended spaces for collaboration. A formative evaluation of DualStream revealed that users valued the ability to interact spatially and move between representations, and could see DualStream fitting into their own remote communication practices in the near future. Drawing from these findings, we discuss new opportunities for designing more widely accessible spatial communication tools, centered around the mobile phone.

Augmented Reality (AR), with its ability to make people feel like they are in the same space as friends from across the world, is an ideal medium for the purpose of Networked Musical Collaboration. Most conventional systems that enable networked musical collaboration minimize network latency by focusing on the transfer of auditory information at the expense of visual feedback. Studies into human perception have shown that sensory integration of audio and visual stimuli can take place even when there is a slight delay between the two signals. We studied the way changes in network latency effect participants’ auditory and visual perception in latency detection, latency tolerance and attention focus; in this paper, we explore the trade-off between the presence of AR visuals and the minimization of latency. Twenty-four participants were asked to play a hand drum and collaborate with a prerecorded remote musician rendered as an avatar in AR. Multiple trials involving different levels of audio-visual latency were conducted. We then analyzed the subjective responses of the participants together with the recorded musical information from each session. Results indicate a minimum noticeable delay value–defined as the highest amount of delay that can be experienced before two stimulated senses are perceived as separate events–between 160 milliseconds (ms) and 320 ms. Players also reported that a delay between sound and an accompanying avatar animation became less tolerable at 320 ms of delay, but was never completely intolerable, even up to 1200 ms of delay. We conclude that players begin to notice delay at about 320 ms and most players can tolerate large delays between sound and animation.

We present Electriflow: a new class of soft electrohydraulic actuators as building blocks for prototyping shape-changing interfaces. These actuators are silent and fast in operation and can be fabricated with commodity materials. Electriflow generates an immediate hydraulic force upon electrostatic activation without an external fluid supply source, enabling a simple and compact self-contained design. This paper describes the materials and mechanisms of these shape-changing building blocks, as well as the underlying fabrication process, which includes a software tool that assists in their design, shape visualization and construction. Finally, we explore four classes of application prototypes: tangible animation, actuating origami creases, shape-changing phone, and shape-changing bowl.

Robotic technologies are becoming pervasive within industrial and domestic settings, resulting in more frequent interactions between humans and robots. To ensure these interactions are effective, Human-Robot Interaction (HRI) researchers have argued that robots and humans must establish a shared common ground by communicating fundamental pieces of information to each other, such as their intentions, goals, plans, status, etc. Although a large body of work has explored how robots might signal individual aspects of such information to users, we still know relatively little regarding the importance of such information overall (e.g., is communicating robot status more important than communicating robot goals?). Such information is necessary for robots acting in the wild to create prioritized lists of communicative goals as, at any given time, it is unlikely that a robot will be able to convey all possibly relevant or important aspects of information to users. Prioritizing information for users is a complex problem as many factors might influence information priority, including task context, user expertise, and robot capability. In this work, we first address the current state-of-the-art signaling methods for non-humanoid robots. Second, we take an initial step towards understanding prioritization by exploring what types of information users request, and how the rankings of informational importance that users assign change, in a prototypical shared-environment interaction with three different types of robots. Our results, collected from 150 participants on Amazon’s Mechanical Turk, generally show that users value information related to the robot’s battery, capabilities, task, safety, navigation, communication, and privacy, with user priorities of these items varying across a small ground robot, a large ground robot, and an aerial robot.

E-textiles, which embed circuitry into textile fabrics, blend art and creative expression with engineering, making it a popular choice for STEAM classrooms [6, 12]. Currently, e-textile development relies on tools intended for traditional embedded systems, which utilize printed circuit boards and insulated wires. These tools do not translate well to e-textiles, which utilize fabric and uninsulated conductive thread. This mismatch of tools and materials can lead to an overly complicated development process for novices. In particular, rapid prototyping tools for traditional embedded systems are poorly matched for e-textile prototyping. This paper presents the ThreadBoard, a tool that supports rapid prototyping of e-textile circuits. With rapid prototyping, students can test circuit designs and identify circuitry errors prior to their sewn project. We present the design process used to iteratively create the ThreadBoard’s layout, with the goal of improving its usability for e-textile creators.

RoomShift is a room-scale dynamic haptic environment for virtual reality, using a small swarm of robots that can move furniture. RoomShift consists of nine shape-changing robots: Roombas with mechanical scissor lifts. These robots drive beneath a piece of furniture to lift, move and place it. By augmenting virtual scenes with physical objects, users can sit on, lean against, place and otherwise interact with furniture with their whole body; just as in the real world. When the virtual scene changes or users navigate within it, the swarm of robots dynamically reconfigures the physical environment to match the virtual content. We describe the hardware and software implementation, applications in virtual tours and architectural design and interaction techniques.

Large-scale shape-changing interfaces have great potential, but creating such systems requires substantial time, cost, space, and efforts, which hinders the research community to explore interactions beyond the scale of human hands. We introduce modular inflatable actuators as building blocks for prototyping room-scale shape-changing interfaces. Each actuator can change its height from 15cm to 150cm, actuated and controlled by air pressure. Each unit is low-cost (8 USD), lightweight (10 kg), compact (15 cm), and robust, making it well-suited for prototyping room-scale shape transformations. Moreover, our modular and reconfigurable design allows researchers and designers to quickly construct different geometries and to explore various applications. This paper contributes to the design and implementation of highly extendable inflatable actuators, and demonstrates a range of scenarios that can leverage this modular building block.

As robots increasingly enter our daily lives, there is a need to understand how to design robots capable of emotional interaction with humans, especially children, due to their sensitivity and vulnerability. For example, robots that provide children with social and emotional support might be more effective at also helping children develop cognitive abilities, rather than designing robots that focus solely on helping children acquire cognitive skill. In this paper, we examine the design of robots that can provide human-like hugs as a particular form of social and emotional support. We first discuss the need to design robots that can interact emotionally with children. Then, we present the development of a shirt augmented with pressure sensors used to collect data on how humans hug each other. Finally, we detail the design of "Hugbot", a soft robot that could use this data to give human-like hugs, and discuss our planned future work on this system.

Recent innovations in fashion and smart textiles have contributed new visions of wearable computing, addressing the body through the cultural and social self. In this work, we draw on speculative design, maker technologies, and zoomorphism to explore how wearables might support sociability, and present Hooze, a fashion accessory that entices touch through its zoomorphic qualities and visual appearance. We describe our design and prototyping process, and reflect on how Hooze inspires transformative designs of wearables.

We present Mechamagnets, a technique for facilitating the design and fabrication of haptic and functional inputs for physical interfaces. This technique consists of a set of 3D printed spatial constraints which facilitate different physical movements, as well as unpowered haptic profiles created by embedding static magnets in 3D printed parts. We propose the Mechamagnets taxonomy to map the design space of this technique for designers and makers. Furthermore, we leverage the use of magnets by instrumenting these objects with linear Hall effect sensors to create functional digital inputs. We showcase Mechamagnets with a series of novel physical interfaces made with this technique.

We introduce shape-changing swarm robots. A swarm of self-transformable robots can both individually and collectively change their configuration to display information, actuate objects, act as tangible controllers, visualize data, and provide physical affordances. ShapeBots is a concept prototype of shape-changing swarm robots. Each robot can change its shape by leveraging small linear actuators that are thin (2.5 cm) and highly extendable (up to 20cm) in both horizontal and vertical directions. The modular design of each actuator enables various shapes and geometries of self-transformation. We illustrate potential application scenarios and discuss how this type of interface opens up possibilities for the future of ubiquitous and distributed shape-changing interfaces.

Creative iterative development over the past several years has generated an extensive set of computational tools, learning resources, and materials in the realm of paper mechatronics - an educational craft and design approach that weaves computational and mechanical elements into established traditions of children's construction with paper. Here, we both reflect upon our past and recent work of paper mechatronics, then look to the near- to medium-term future to speculate upon both the emerging trends in technology design and expanding learning potential of this medium for children along material, spatial, and temporal dimensions. We summarize lessons learned through various children's workshops with our materials; and we use these lessons as a foundation upon which to create a wide variety of novel tools and activities in educational papercrafting. We speculate upon the frontiers of this work based on current convergences and shifts in tangible creative computational media.

We present PEP (Printed Electronic Papercrafts), a set of design and fabrication techniques to integrate electronic based interactivities into printed papercrafts via 3D sculpting. We explore the design space of PEP, integrating four functions into 3D paper products: actuation, sensing, display, and communication, leveraging the expressive and technical opportunities enabled by paper-like functional layers with a stack of paper. We outline a seven-step workflow, introduce a design tool we developed as an add-on to an existing CAD environment, and demonstrate example applications that combine the electronic enabled functionality, the capability of 3D sculpting, and the unique creative affordances by the materiality of paper.

We explore a new approach to programming swarm user interfaces (Swarm UI) by leveraging direct physical manipulation. Existing Swarm UI applications are written using a robot programming framework: users work on a computer screen and think in terms of low-level controls. In contrast, our approach allows programmers to work in physical space by directly manipulating objects and think in terms of high-level interface design. Inspired by current UI programming practices, we introduce a four-step workflow-create elements, abstract attributes, specify behaviors, and propagate changes-for Swarm UI programming. We propose a set of direct physical manipulation techniques to support each step in this workflow. To demonstrate these concepts, we developed Reactile, a Swarm UI programming environment that actuates a swarm of small magnets and displays spatial information of program states using a DLP projector. Two user studies-an in-class survey with 148 students and a lab interview with eight participants-confirm that our approach is intuitive and understandable for programming Swarm UIs.

This paper introduces Dynamic 3D Printing, a fast and reconstructable shape formation system. Dynamic 3D Printing can assemble an arbitrary three-dimensional shape from a large number of small physical elements. Also, it can disassemble the shape back to elements and reconstruct a new shape. Dynamic 3D Printing combines the capabilities of 3D printers and shape displays: Like conventional 3D printing, it can generate arbitrary and graspable three-dimensional shapes, while allowing shapes to be rapidly formed and reformed as in a shape display. To demonstrate the idea, we describe the design and implementation of Dynablock, a working prototype of a dynamic 3D printer. Dynablock can form a three-dimensional shape in seconds by assembling 3,000 9 mm blocks, leveraging a 24 x 16 pin-based shape display as a parallel assembler. Dynamic 3D printing is a step toward achieving our long-term vision in which 3D printing becomes an interactive medium, rather than the means for fabrication that it is today. In this paper, we explore possibilities for this vision by illustrating application scenarios that are difficult to achieve with conventional 3D printing or shape display systems.

For people with visual impairments, tactile graphics are an important means to learn and explore information. However, raised line tactile graphics created with traditional materials such as embossing are static. While available refreshable displays can dynamically change the content, they are still too expensive for many users, and are limited in size. These factors limit wide-spread adoption and the representation of large graphics or data sets. In this paper, we present FluxMaker, an inexpensive scalable system that renders dynamic information on top of static tactile graphics with movable tactile markers. These dynamic tactile markers can be easily reconfigured and used to annotate static raised line tactile graphics, including maps, graphs, and diagrams. We developed a hardware prototype that actuates magnetic tactile markers driven by low-cost and scalable electromagnetic coil arrays, which can be fabricated with standard printed circuit board manufacturing. We evaluate our prototype with six participants with visual impairments and found positive results across four application areas: location finding or navigating on tactile maps, data analysis, and physicalization, feature identification for tactile graphics, and drawing support. The user study confirms advantages in application domains such as education and data exploration.

This studio invites participants to design and build machines with different kinds of paper and craft materials. We will introduce papercrafting using our design tool "FoldMecha", mechanical components, and prototyping methods for physical construction.

We present FoldMecha, a computer-aided design (CAD) system for exploratory construction of mechanical papercraft. FoldMecha enables students to (a) design their own movements with simple mechanisms by modifying parameters and (b) build physical prototypes. This paper describes the system, as well as associated prototyping methods that make the construction process easier and more adaptable to widely different creations. The paper also discusses a week-long workshop that we held with six teenagers using FoldMecha. The teens successfully designed and built their own mechanisms, and adapted them to a variety of creations. Throughout the workshop, they progressively achieved an advanced level of skill and understanding about mechanical movements.

We present a kit comprising cardboard mechanical components and a custom printed circuit board, designed to support novices in building computational percussive instruments with everyday materials. We set three design criteria: accessibility, adaptability, and expressivity. We conducted two workshops with experts and novices to assess the usability of our kit and observe the variety of constructions that users make. The kit enabled both experts and novices to build working instruments and to explore creative experimentation with different materials and objects.

Paper Mechatronics is a novel interdisciplinary design medium for children, enabled by recent advances in craft technologies: the term refers to a reappraisal of traditional educational papercrafts in combination with accessible mechanical, electronic, and computational elements. We present a design case study--building computationally-enhanced paper flowers--and discuss the iterative design process involved in the creation. We also describe a workshop we conducted with teenagers to evaluate paper mechatronics as a creative learning activity for children. We conclude with a discussion of future directions.

We present a modular tangible user interface system and corresponding actuators for creating music with everyday objects. Users create percussive patterns by controlling algorithmic parameters, or by directly playing the interface. Various mechanical solutions allow users to investigate physical objects as sound sources. A standalone physical interface and an associated graphical programming environment enable different levels of user engagement and hardware/software transparency. We discuss a tool space in-between open and closed design concepts, as well as the physical and software design of the Kitsch-Instrument itself. We also describe recent interactions with the interface at a public event and discuss future plans.

We present Cube-in, a kit designed to help beginners learn about fundamental concepts in physical computing. Through play and observation, Cube-in users can investigate digital and analog signals, inputs and outputs, and mapping between inputs and outputs before they work on electronics and construct circuits. By simplifying interaction methods, Cube-in provides an accessible entry point to key physical computing concepts.

Giffi is a computationally enhanced construction kit that enables children to build kinetic forms through purposeful play and discovery.

Spectacle computing is a novel strategy for vibrantly projecting information into the public sphere using expressive and tangible media. We demonstrate an example of this computing meme with large, glowing balloons that change color based on input from attached air quality sensors (exhaust, diesel, or volatile organic compounds). In two public installations (city street and public park) and a deployment with six everyday citizens, we invited stakeholders to playfully explore and actively participate in visualizing surrounding air quality. We also created a do-it-yourself (DIY) kit that includes a printed circuit board, electronic parts and instructions for building the air quality balloons. In a workshop, six non-expert users successfully assembled functional balloons, validating our technology as a DIY tool for public air quality visualization. Our deployments and workshop highlight play and spectacle as essential elements for public participation and activism. We outline design guidelines for future spectacle computing projects that engage stakeholders with environmental data and empower them to transform urban landscapes.

The TEI Work-in-Progress workshop invited submissions about designing, making, studying, exploring and experiencing of projects on tangible, embedded and embodied interaction. The workshop aimed to provoke, intrigue, and inspire the TEI community by sharing work-in-progress practice, late breaking innovation, cutting-edge research, and controversial and compelling work. It provided a venue for eliciting feedback and fostering discussions and collaborations among TEI colleagues. The TEI Work-in-Progress workshop provided an opportunity for members of the TEI community with common and diverse interests to meet in the context of a focused and interactive discussion and a showcase for exciting new work that is still at an early stage.

We present a series of prototype devices that use real-time input to fabricate physical form: Interactive Fabrication. Our work maps out the problem space of real-time control for digital fabrication devices, and examines where alternative interfaces for digital fabrication are relevant. We conclude by reflecting upon the potential of interactive fabrication and outline a number of considerations for future research in this area.

This paper presents the concept and the design of an ambient display with an anthropomorphic interface to communicate environmental data. Numeric display and control, as in a thermostat, is replaced by a digital interactive portrait with the aim of making interaction engaging and undemanding.

Street art and political activism have a rich history of shaping urban landscapes. Our work explores the processes by which public artists and political activists contribute to public spaces, introducing opportunities for HCI researchers to engage with the people who shape the aesthetic feel of our cities. We present WallBots-autonomous, wall-crawling robots as a research probe for public expression across a wide range of surfaces and hard-to-reach places, including bus stops, whiteboards, streetpoles, trashcans, moving vehicles and building walls. We evaluate WallBots as a low-cost DIY authoring tool for public artists and activists. Our study of six individuals who extensively contribute to public spaces offers insights into the materials and practices behind grassroots public expression. We then leverage feedback from participants, among them a graffiti artist, light painter, political activists, and street musician, to evaluate interaction techniques for manipulating WallBots as a medium for public expression across a range of surfaces. Our findings expose a research space for technological interventions in the context of street art, and we conclude with design insights for magnetic kinetic systems as an approach for supporting engagement, expression and creativity in public spaces.

To accommodate frequent emergencies, interruptions, and delays, hospital staff continually make and coordinate changes to the surgery schedule. The technical and social aspects of coordination in surgical suites have been described by prior studies. This paper addresses an understudied aspect of coordination: the physical environment. Based on a field study of four surgical suites in two large academic centers, we show how the physical layout of hallways and rooms, and barriers and spaces around displays and key coordinators, support or fail to support the common information spaces used for coordination. We use the concept "information hotspots" to represent how physical places and their characteristics facilitate coordination. We developed design principles based on the concept of information hotspots that should guide architectural considerations for coordination in dynamic environments such as hospitals.

We designed and prototyped WearAir, an expressive T-shirt to sense the wearer's surrounding air quality as indicated by the measured volatile organic compounds (VOCs) and publicly express those levels through visually expressive patterns. Although poor air quality has been shown to affect human health, our daily exposure to such pollutants has been inadequately captured and publicly shared. Our work is designed to accurately measure and publicly express the immediately local air quality. Obtaining information regarding air quality indirectly from others might help people to increase their awareness to air quality.

We describe a family of interactive devices made from paper and simple electronics: Paper Robots, Paper Speakers and Paper Lamps. We developed construction techniques for these paper devices and the Paper Factory software with which novice users can create and build their own designs. The process and materials support DIY design and could be used with low-cost production and shipment from an external service.

We developed Escape Machine, a puzzle game in which children control the behavior of characters in a maze by manipulating a tangible state machine built with Posey, our computationally-enhanced hub-and-strut construction kit. We observed children ages nine to eleven playing the game in several sessions. The qualitative results of this observation validate the promise of Posey and Escape Machine to engage children in manipulating algorithmic specifications for behavior.

The prismatic cube style of modular robot is a promising design for realizing self-reconfigurable 3D lattices. Cubic lattices with prismatic transitions simplify many aspects of the hardware and planning control needed for reconfiguration. Despite much research on how cubic modules can coordinate to reconfigure, until now these transitions have not been fully demonstrated in hardware.We describe our movement primitives for both orthogonal and convex corner transitions with prismatic cube modules. We discuss the design of a hardware module capable of performing these transitions, as well as assess the performance of this hardware in an initial demonstration of these transitions.

Easigami is a novel tangible user interface (TUI) and interactive system intended to help children to learn to fold 3D geometric forms and to explore 2D-3D transformations. We present the design of Easigami's physical interface: a reconfigurable system of thin flat polygon pieces connected by electronically instrumented hinges. Using the Easigami TUI as an input device, we have developed early prototype applications to develop children's visualization and spatial recognition skills. We discuss our experience in integrating traditional craft with computation, which may inform future tangible and graspable user interface design.

Graphs are a versatile representation of many systems in computer science, the social sciences, and mathematics, but graph theory is not taught in schools. We present our work on Graphmaster, a computationally enhanced construction kit that enables children to build graphs of their own and investigate their properties by experimenting with algorithms that operate on them. The system is distributed; microcontrollers inside each node execute an interpreted language in parallel. Graphmaster, with its magnetic connectors, illuminated edges, and capacitive sensing, encourages children to develop intuitions about connectivity long before they are introduced to the notation and formulas of graph theory.

We present a methodology for building objects-to-think-computationally-with and illustrate its application in developing our Escape Machine game. The input mechanism for this game is a tangible state machine built with Posey, our computationally enhanced construction kit. Through manipulating this state machine children create an algorithmic specification for the behavior of both the avatar and its enemies in an attempt to navigate a maze without being eaten. We outline several strategies for success at Escape Machine and discuss how it embeds an important computational thinking concept in interaction with a tangible device.

The roBlocks construction kit is a tangible concurrent programming environment that encapsulates sensory, kinetic, and computational behavior in modular building block units that snap together to construct robots. The choice of a protocol for propagating values through the constructed robot affects its behavior.

We describe Posey, a computationally-enhanced hub-and-strut construction kit for learning and play. Posey employs a ball and socket connection that allows users to move the parts of an assembled model. Hubs and struts are optocoupled through the ball and socket joints using infrared LEDs and photosensors. Wireless transmitters in the hubs send connection and geometry information to a host computer. The host computer assembles a representation of the physical model as the user creates and configures it. Application programs can then use this representation to control computational models in particular domains.

We have, with our students, engaged in cross-disciplinary research in design. We describe parameters and principles that we have found helpful in organizing and conducting this kind of work. A variety of projects that have been developed in our group illustrate these parameters and principles. Our group focuses on making and we have come to see creativity as grounded in the ability to make things.

Flow selection is a time-based modeless selection and operation technique for freehand drawing and sketch tools. We offer flow selection as a modeless technique to address the observation that modal selection requires too much cognitive effort and causes breakdowns in creative flow. Flow selection provides input to a new class of operations by assigning increasing, fractional selection strengths to objects over time. We discuss the current prototype system and possible applications for this novel technique for interacting with sketches.

We describe work in progress on roBlocks, a computational construction kit that encourages users to experiment and play with a collection of sensor, logic and actuator blocks, exposing them to a variety of advanced concepts including kinematics, feedback and distributed control. Its interface presents novice users with a simple, tangible set of robotic blocks, whereas advanced users work with software tools to analyze and rewrite the programs embedded in each block. Early results suggest that roBlocks may be an effective vehicle to expose young people to complex ideas in science, technology, engineering and mathematics.

The Navigational Blocks project demonstrates a tangible user interface that facilitates retrieval of historical stories in a tourist spot. Orientation, movement, and relative positions of physical Blocks support visitor navigation and exploration in a virtual gallery. The Navigational Blocks system provides a physical embodiment of digital information through tactile manipulation and haptic feedback. The simple cubic form of the Blocks is easy to understand and therefore easy to use to manipulate complex digital information. Electromagnets embedded in the Blocks and wireless communication encourage users to quickly rearrange the Blocks to form different database queries.

This paper reports on our progress and findings in building a Web annotation system for non-immersive 3D virtual environments. Over the last two years, we developed and tested two systems for collaborating designers to comment on virtual 3D models. Our first system, Redliner [12] lets design team members browse and leave text annotations on surfaces in three-dimensional models. Experience with Redliner, including two user evaluations in different settings, led us to develop Space Pen [13], a second annotation system with improved interaction capabilities. It goes beyond the post-it note metaphor, allowing users to draw in and on the virtual environment.

Interfaces for conceptualand creative design should recognize and interpret drawings.They should also capture users' intended ambiguity, vagueness, and imprecision and convey these qualities visually and through interactive behavior.Freehand drawing can provide this information and it is a natural input mode for design.We describe a pen-based interface that acquires information about ambiguity and precision from freehand input, represents it internally, and echoes it to users visually and through constraint based edit behavior.

Architectural designers are voracious consumers of visual images, which play a crucial role especially in conceptual and creative design. Consequently architectural education revolves around visual references. Yet key word, texture and color retrieval schemes do not suit designers' needs. Designers need shape based retrieval that is driven by free hand drawing, and ways to integrate retrieved images into their design environment. The paper describes Drawing Analogies, an image retrieval scheme for design based on the need for image retrieval that can be integrated with the act of free hand drawing. Our scheme does not perform feature extraction of stored images, but relies on users to create an index of diagram keys.

Abstract The following paper describes a new approach for the automatic segmentation and tissue classification of anatomical objects such as brain tumors from magnetic resonance imaging (MRI) data sets using artificial neural networks. These segmentations serve as an input for 3D–reconstruction algorithms. Since MR images require a careful interpretation of the underlying physics and parameters, we first give the reader a tutorial style introduction to the physical basics of MR technology. Secondly, we describe our approach that is based on a two–pass method including non–supervised cluster analysis, dimensionality reduction and visualization of the texture features by means of nonlinear topographic mappings. An additional classification of the MR data set can be obtained using a post–processing technique to approximate the Bayes decision boundaries. Interactions between the user and the network allow an optimization of the results. For fast 3D–reconstructions, we use a modified marching cubes algorithm but our scheme can easily serve as a preprocessor for any kind of volume renderer. The applications we present in our paper aim at the automatic extraction and fast reconstruction of brain tumors for surgery and therapy planning. We use the neural networks on pathological data sets and show how the method generalizes to physically comparable data sets.