sketchpad

sketchpad - S KETCH PAD This paper was reproduced from the...

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SKETCH PAD This paper was reproduced from the AFIPS Conference proceedings, Volume 23, of the Spring Joint Computer Conference held in Detroit, 1963. Mr. Timothy Johnson suggested that this report contained essentially the same material he spoke on at the SHARE D/A Committee Workshop. T. E. JOHNSON M.I.T. CAMBRIDGE, MASSACHUSETTS
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y SKETCHPAD A MAN-MACHINE GRAPHICAL COMMUNICATION SYSTE Ivan E. Sutherland Consultant, Lincoln Laboratory** Massachusetts Institute of Technology I. INTRODUCTION The Sketchpad system makes it possible for a man and a computer to converse rapidly through the medium of line drawings. Here- tofore, most interaction between man and com- puters has been slowed down by the need to reduce all communication to written statements that can be typed; in the past, we have been writing letters to rather than conferring with our computers. For many types of communica- tion, such as describing the shape of a me- chanical part or the connections of an electrical circuit, typed statements can prove cumber- some. The Sketehpad system, by eliminating typed statements (except for legends) in favor of line drawings, opens up a new area of man- machine communication. AN INTRODUCTORY EXAMPLE To understand what is possible with the sys- tem at present let us consider using it to draw the hexagonal pattern in Figure 4. We will issue specific commands with a set of push but- tons, turn functions on and off with switches, indicate position information and point to exist- ing drawing parts with the light pen, rotate and magnify picture parts by turning knobs, and observe the drawing on the display system. This equipment as provided at Lincoln Labora- tory's TX-2 computer 1 is shown in Figur When our drawing is complete it may be in on paper, as were all the drawings in this pa by a PACE plotter, is If we point the light pen at the display tem and press a button called "draw," the c puter will construct a straight line segm which stretches like a rubber band from Figure I. TX-2 operating areawSketchpad in use. the display can be seen part of a bridge similar to t of Figure 15. The Author is holding the light pen. push buttons "draw," "move," etc., are on the box front of the Author. Part of the bank of toggle switc can be seen behind the Author. The size and positio the part of tne total picture seen on the display controlled by the four black knobs just above the tab * This paper is based in part on a thesis submitted tothe Department of Electrical Engineering, M.I.T., in partial fulfillment of the requirements for the Degree of Doctor of Philosophy. ** Operated with the support of the U.S. Army, Navy, and Air Force. . 329
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330 PROCEEDINGS~SPRING JOINT COMPUTER CONFERENCE, 1963 initial to the present location of the pen as shown in Figure 2. Additional presses of the button will produce additional lines, leaving the closed irregular hexagon shown in Figure 3A. To make the hexagon regular, we can inscribe it in a circle. To draw the circle we place the light pen where the center is to be and press the
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sketchpad - S KETCH PAD This paper was reproduced from the...

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