Drawing a circle is performed by pressing the "circle" button, moving the stylus to the desired radius, and lifting it from the screen. In both Sketchpad and the reconstruction, three interactions are needed to draw an arc - setting the center, radius, and sweep - but we simplify circles to require only two interactions. Whereas Sketchpad afforded only circular arcs (which could be partial segments or complete circles), the reconstruction differentiates between arcs and circles. Printed instructions guide visitors to the reconstruction through the process of creating and manipulating drawings. Here, the "termination flick" is performed instead by simply lifting the stylus from the screen. In Sketchpad, a user finishes drawing a line by giving the "termination flick," literally flicking the pen in any direction quickly enough that the display loses tracking and leaves the active end of the line where it was. Whereas the light pen should be held near the display screen, the stylus must touch the screen directly. Again, rather than a light pen, their is a touch-screen stylus.
The reconstruction affords a similar experience for creating drawings, with some key differences. It is also possible to create compound objects, such as (for example) a triangle inscribed in a circle, and for the individual entities to then act as one - moving, scaling, rotating, copying, and deleting in tandem.Īn early video prototype demonstrating the Sketchpad reconstruction's capabilities: Drawing, moving, copying, deleting, and creating compound objects. A user may draw these to the screen, and retain the ability to move, manipulate, copy, and delete the graphical objects.
#Sketchpad sutherland software#
Because of this, there are several more layers of abstraction mediating between the software description of an object and its representation in memory.ĭrawing from Sutherland’s thesis, contemporary video documentation, and interviews with users of the original system, the reconstruction allows users to create and manipulate geometric entities including lines, arcs, and circles.
#Sketchpad sutherland android#
Whereas Sutherland programmed Sketchpad in a low-level assembly language directly on the TX-2 computer, this reconstruction paradigm uses Java running on an Android tablet. There are important differences between this software reconstruction and the original Sketchpad, owing to advances in software development, and to simplify some of the complexities of the original while retaining its character as a software artifact.
#Sketchpad sutherland series#
The TX-2’s original user interface of flywheels, switches, and a keyboard are imitated using the tablet, a series of control knobs, a keypad, and stylus at a custom-built work station.Įarly axonometric drawing of plywood work station construction Software For example, in place of the light pen control, there is a stylus for the Android tablet: Readily available tools requiring little additional hardware integration. Rather than a detailed replica, this reconstruction relies on modern devices to evoke visual, gestural, and ergonomic aspects of Sketchpad. Visitors interacting with the reconstruction can be draw and manipulate geometric shapes in ways that evoke Sutherland’s original system. Its key elements are a "light pen," a keypad, and a 7" x 7" screen. Looking at that video, it's just amazing to think of that kind of tech in 1963.This piece, originally built for the 2017 Designing the Computational Image, Imagining Computational Design exhibition at Carnegie Mellon University, approximates the ergonomics of the TX-2 computer, on which Ivan Sutherland developed Sketchpad in his 1963 dissertation. Fast-forward to today and the video is only a YouTube search away." I had the fortune in the mid-'90s to watch a rare videocassette recording of Alan Kay describing Sketchpad for a computer graphics course taught by Randy Pausch. Today I recalled Ivan Sutherland's Sketchpad, arguably the most significant Computer Science Ph.D. You stash that date in the back of your mind only to recall it much later in life, surprised and chagrined at the time that's passed since you last thought of it. He writes, "Sometimes you're told something that happened some time ago. Today's video was pointed out by Charles Choi over on his Notes from /dev/null blog. Long before Apple, the Lisa and Xerox's Alto, a constraint-based object-oriented graphical system was developed and demonstrated. Fifty years ago in 1963, Ivan Sutherland first demonstrated Sketchpad, one of the most important contributions to the field of Computer Science.
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