![]() ![]() Now, at the age of 74, he is heading up research in asynchronous computing at Portland State University.Īs a result of his work on Sketchpad, and his many subsequent contributions to computing, Sutherland has received a dazzling array of honors, including the National Academy of Engineering First Zworykin Award, the IEEE Emanuel R. He taught at Harvard, University of Utah, and Caltech. He was a Fellow and Vice President at Sun Microsystems. He co-founded Evans and Sutherland, where he did pioneering work in the field of real-time hardware, accelerated 3D graphics, and printer languages. He went on to run ARPA (the predecessor of DARPA.) He co-created the first virtual reality and augmented reality head-mounted display. Sutherland didn’t rest on his laurels after Sketchpad. If you use a computer or smart phone, you’re using technology pioneered by Sketchpad. ![]() Sketchpad pioneered some of the most important concepts in computing, including the graphical user interface, non-procedural programming, and object-oriented programming. Just search for “Ivan Sutherland.”) Further, both Sutherland and Johnson presented papers on their work at the 1963 Spring Joint Computer Conference. (A film that appears to be an edited version of this is on YouTube. A combination of these films was used in a 30-minute program in 1964 for Boston TV station WBGH. While it’s likely that Sketchpad would have gotten plenty of attention on its own, Sutherland, Johnson, and Roberts each made 16 mm movies, demonstrating their work. Roberts submitted his PhD thesis, where he had added support to Sketchpad for 3D solids, including assemblies and real-time hidden line removal. Shortly after Sutherland submitted his Sketchpad thesis, Timothy E Johnson submitted his Masters thesis describing Sketchpad III, a 3D version of the program. Sketchpad was designed to be extensible, with provision for adding both new graphical element types, and new constraint types. It supported rubberbanding when drawing or editing entities (so the entities would stretch as you moved the cursor.) It supported dynamic move, rotate, and scale of entities (meaning that they moved, rotated, and scaled as you moved the cursor.) It not only supported zoom and pan (dynamically, of course), but did so transparently-even when you were in the midst of another drawing or editing operation. Visually, Sketchpad was surprisingly interactive. It was even possible to use constraints to do structural analysis of lattice trusses, such as might be found on cantilever and arch bridges. With the constraint system, it was possible to loosely sketch a shape, then add geometric and topological relationships to modify it into the exact shape you needed. Sketchpad even allowed the visual display of constraints on screen, using icons (symbols) to represent each type. These native (or “atomic”) constraints could be combined, to create more complex relationships. Sketchpad included 17 different types of constraints, including vertical, horizontal, perpendicular, coincident, parallel, aligned, equal size, and more. If, while editing, you moved one line, the other line would move with it. And it would remember that the two lines were connected. For example, if you started to draw a line, and brought the cursor close to the endpoint of another line, it would snap to that endpoint. It not only supported explicit constraints, added to entities after they were drawn, it supported implicit constraints, created as entities were drawn. One thing that made Sketchpad really stand out was its constraint management subsystem. This facility was used to create alphanumeric character glyphs, and electrical schematic symbols. The program supported points, line segments, and arcs as basic elements, but allowed these to be saved into master drawings, which could be copied or instanced. ![]() Using the light pen and input buttons, you could draw directly on the screen, using a crosshair cursor. Unlike earlier computer applications, which were batch oriented, Sketchpad was interactive. Ivan Sutherland on MIT Lincoln Labs’ TX-2 computer.
0 Comments
Leave a Reply. |