Sketchpad : A Man-Machine Graphical Communication System

by Ivan Sutherland

Summary

This paper is about Sutherland's graphical interaction system, it should be noted that the paper was published in 1963. The paper opens with a great quote "Heretofore, most interaction between man and computers has been slowed down by the need to reduce all communications to written statements that can be typed; in the past, we have been writing letters to rather than conferring with computers." The paper opens with an example of drawing a hexagon shape: the drawing is accomplished with a light pen and a variety of buttons and knobs. The light pen is used to draw the line, by way of rubber bad, and the other inputs are used to constrain the drawing. Throughout the paper Sutherland makes many references that are similar to object oriented programming concepts (such as "instance" and inheritance). He also notes that not only is the drawing stored, but information about its creation (constraints is stored). Changing the basic shape, if instances of that shape have been used ripples through the document. The paper notes four broad areas in which such a system is useful: storing and updating drawings, gaining scientific or engineering understanding of operations that can be described graphically, topological input for circuit simulators and highly repetitive drawings. The paper describes the ring structure, light pen and display technology that was used in the system. Also discussed is the abstraction, the recursive merging and deleting. Of note is the discussion of how constraints can be put onto already created drawings. The paper lists patterns, linkages, dimensional lines, bridges, artistic drawings and electrical circuit diagrams as domain examples.

Discussion

Sutherland, could for see the issue I would have when he put the sentence, "It is only worthwhile to make drawings on the computer if you can get something more out of the drawing than just a drawing" into the conclusion. This is one of those papers that I always get a weird feeling about. Sure, 1963, and it was an incredible break through. He did amazing things. My concern is that for one reason or another these ideas did not catch on. This wasn't some nameless researcher, Sutherland is widely respected. He was at MIT, he had funding. It is because the possible uses are limited? Have we become so use to keyboard/mouse interaction that what was once considered a more natural input technique (pen) is no longer natural?

Citation

Sutherland, I. E. 1964. Sketch pad a man-machine graphical communication system. In Proceedings of the SHARE Design Automation Workshop DAC '64. ACM Press, New York, NY, 6.329-6.346. DOI= http://doi.acm.org/10.1145/800265.810742

Introduction to Sketch Recognition

by Tracy Hammond and Kenneth Mock

Summary

The paper discusses pen based computing and sketch recognition with particular attention paid towards educational environments. Background is given on the creation of the field, specifically Ivan Sutherland's early contributions. Tablet PCs are described as well as the distinction between passive (that which requires contact) and active (that which requires a special stylus) digitizers. Also described are different pen input devices (tablets, UMPC, drawing tablets) and the software that can be used with such input means. The paper focuses then on this type of input in educational situations. How lectures can be annotated, edited, and prepared using pen input is discussed.

The paper then moves into a discussion of sketch recognitions and lists domains - art, music, chemistry, mathematics, finite-state machines, UML, COA - in such recognition makes sense. The paper also gives a brief overview of FLUID (LADDER and GUILD), and comments on how sketches can be tied to higher-level functionality. The authors describe how shape definitions are created in LADDER using primitive shapes and constraints. Also noted are two challenges with pen-input: 1) recognization systems being able to handle varied input, 2) administrative concerns. The authors then discuss two case studies of tablet use in classrooms. The paper concludes noting the increase in TabletPC's adoption in educational markets.

Discussion

Both of the case studies take place in Math classes: it would have been better to have each case study focus on a different subject. The paper gives a good overview of current pen input devices, those devices' roles in an education environment, and what is happening in sketch recognition. The work was a bit fluffy, but the author openly admits that.

Something that concerns me about sketch recognition is that it seems heavily domain specific. I have difficulty moving beyond the "that's neat" feeling into viewing it as something that can have a fundamental shift in the way people interact with computers.

Play this game, how would you want to interact with a computer if anything was possible? Paper has some great benefits, but far too many of them I feel are physical not the user interface. By physical I mean the lightness, the contrast. In pen input I lose some of those nice physical qualities but I gain the nice digital ones (the ability to edit, the ability to reproduce, the ability to collaborate over a large distance).