Magic Windows: W3 Reading – Bricks: Laying the Foundations for Graspable User Interfaces

Bricks: Laying the Foundations for Graspable User Interfaces

An argument for virtual items having physical forms. That physical items allow for richer interactions /affordances that ” include facilitating two handed interactions, spatial caching, and parallel position and orientation control”.
This paper was publiched in the ACM proceedings of CHI ’95 by George Fitzmaurice, Hiroshi Ishii, and William Buxton.  It Introduces the concept of Graspable User Interfaces which allow for control of electronic or virtual objects via physical control handles. The “bricks” are physical objects that function as input devices paired to virtual objects for manipulation or expressing an action. They work with a large display surface that they deemed the “active desk”. In the paper they present 4 stages:
    • series of exploratory studies on hand gestures / grasping
    • interaction simulations using mockups / rapid prototyping tool
    • working prototype and sample application called GraspDraw
    • initial integration of graspable UI concepts into a commercial application


Space multi-plexed object 
With space-multiplexed input, each function to be controlled has a dedicated transducer, each occupying its own space. For example, an automobile has a brake, clutch, throttle, steering wheel, and gear shift which are distinct, dedicated transducers controlling a single specific task.” 
Time multi-plexed object 
“uses one device to control different functions at different points in time. For instance, the mouse uses time multiplexing as it controls functions as
diverse as menu selection, navigation using the scroll
widgets, pointing, and activating “buttons.””
GUIs as an example of dissonance
the display output is often space-multiplexed (icons or control widgets occupytheir own space and must be made visible to use) while the input is time-multiplexed (i.e., most of our actions are channeled through a single device, a mouse, over time). Only one task, therefore, can be performed at a time, as they all use the same transducer. The resulting interaction techniques are often sequential in nature and mutually exclusive.” 
The Graspable UI philosophy as proposed solution for this dissonance (bullets from paper)
    • “It encourages two handed interactions [3, 7];
    • shifts to more specialized, context sensitive input devices;
    • allows for more parallel input specification by the user, thereby improving the expressiveness or the communication capacity with the computer;
    • leverages off of our well developed, everyday skills of prehensile behaviors [8] for physical object manipulations;
    • externalizes traditionally internal computer representations;
    • facilitates interactions by making interface elements more “direct” and more “manipulable” by using physical artifacts;
    • takes advantage of our keen spatial reasoning [2] skills;
    • offers a space multiplex design with a one to one mapping between control and controller; and finally,
    • affords multi-person, collaborative use.”
KEYWORDS: input devices, graphical user interfaces,
graspable user interfaces, haptic input, two-handed
interaction, prototyping, computer augmented environ-
ments, ubiquitous computing
Basic Concepts 
Additional Word Bank:


  • transducer – a device that converts energy from one form to another
  • multiplexing –  “method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephonyGeorge Owen Squier is credited with the development of telephone carrier multiplexing in 1910.”
    • think back to pcomp/icm exploration
  • space-multiplexed 
  • time-multiplexed 
  • paradigm – a typical example or pattern of something; a model.
  • concurrence – the fact of two or more events or circumstances happening or existing at the same time.
  • haptic technology


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