![]() For example, to make two lines parallel, he successively points to the lines with the light pen and presses a button. The user indicates conditions with the light pen and push buttons. Sketchpad itself is able to move parts of the drawing around to meet new conditions which the user may apply to them. Since Sketchpad is able to accept topological information from a human being in a picture language perfectly natural to the human, it can be used as an input program for computation programs which require topological data, e.g., circuit simulators. The topological connections of the drawing are automatically indicated by the user as he sketches. If the user moves a symbol, all lines attached to that symbol will automatically move to stay attached to it. If the user moves one vertex of a polygon, both adjacent sides will be moved. Sketchpad stores explicit information about the topology of a drawing. Any change in the definition of a symbol is at once seen wherever that symbol appears. A user may define and use as many symbols as he wishes. Arbitrary symbols may be defined from any collection of line segments, circle arcs, and previously defined symbols. Information sketched can include straight line segments and circle arcs. A set of push buttons controls the changes to be made such as “erase”, “move”, etc. Sketchpad also makes it easy to draw highly repetitive or highly accurate drawings and to change drawings previously drawn with it.Ī Sketchpad user sketches directly on a computer display with a “light pen.” The light pen is used both to position parts of the drawing on the display and to point to them to change them. Sketchpad has shown the most usefulness as an aid to the understanding of processes, such as the notion of linkages, which can be described with pictures. It was a general purpose system and has been used to draw electrical, mechanical, scientific, mathematical, and animated drawings. The system contains input, output, and computation programs which enable it to interpret information drawn directly on a computer display. The Sketchpad uses drawing as a novel communication medium for a computer. Sketchpad was able to do just this, creating highly precise drawings, and also introduced important innovations such as memory structures to store objects and the ability to zoom in and out. He imagined that one should be able to draw on the computer. TX-2 included a nine inch CRT and a light pen which first gave Sutherland his idea. ![]() Sketchpad ran on the Lincoln TX-2 computer, an innovative machine designed in 1956 (it had a large amount of memory for its time: a vacuum-tube-driven core of 64K words, a faster, transistor-driven core of 4K words, a paper-tape reader and could also use magnetic tape as auxiliary storage.) TX-2 was an “on-line” computer (at that time most computers would run “batches” of jobs and were not interactive), used to investigate the use of Surface Barrier transistors for digital circuits. Sketchpad, in turn, influenced Douglas Engelbart’s NLS (oN-Line System). Sketchpad was influenced by the conceptual Memex of Vannevar Bush, as it was envisioned in his fundamental paper “As We May Think”. For his Ph.D., Sutherland went to MIT (Massachusetts Institute of Technology) were he studied under Claude Shannon and Marvin Minsky and developed his revolutionary thesis, Sketchpad, A Man-Machine Graphical Communication System, the first Graphical User Interface. also in Electrical Engineering from the Caltech (California Institute of Technology). Sutherland went on the study at Carnegie Mellon University, where he earned a Bachelor’s degree in Electrical Engineering and then went on to earn a M.S. Ivan and his brother Bert even met Berkeley and were inspired to envision new avenues for programming. This program was a great accomplishment, it was the longest program ever written for Simon, a total of eight pages of paper tape. To make division possible, he added a conditional stop to Simon’s instruction set. Ivan’s first big computer program was to make Simon divide. His first computer experience was with the famous computer Simon of Edmund Berkeley. He introduced concepts such as 3-D computer modeling, visual simulations, computer aided design (CAD), virtual reality, etc. thesis, named Sketchpad, which is one of the most influential computer programs ever written by an individual, Sutherland has contributed numerous ideas to the study of Computer Graphics and Computer Interaction. Ivan Sutherland is considered by many to be the creator of Computer Graphics and an Internet pioneer.
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