Sketchpad was an innovative computer program developed by Ivan Sutherland in 1963 for his PhD thesis. Sketchpad paved the way for human-computer interaction (HCI). Sketchpad is considered the ancestor of contemporary computer-aided design (CAD) programs. It is also regarded as a significant advancement in computer graphics development. For instance, cutting-edge object-oriented programming as well as the graphical user interface (GUI) was based on Sketchpad.
In 1988 and 2012, Ivan Sutherland received the Turing Award and the Kyoto Prize, respectively, for designing Sketchpad.
By introducing Sketchpad, Ivan Sutherland showcased that computer graphics can be put to use for both technical and artistic purposes other than using it as a novel method of HCI. It had the ability to support constraints, for example, sketching a constrained ellipse created a circle. Sketchpad sported some CAD features as well, for example, computing loads on beams.
Sketchpad permitted users to sketch on a screen using a light pen. It solved constraints with the help of value inference and presented the "ring" list framework. The drawings done using Sketchpad were stored in this specially engineered ring structure within the computer. This ring structure included instant processing of topological information, which required no searching at all.
Sketchpad operated on the Lincoln TX-2 computer, which was a revolutionary machine developed in 1956. It was an "online" computer designed to check the usage of surface-barrier transistors for digital circuits.
Sketchpad made use of drawing as a computer's unique interaction medium. The system consisted of input, output as well as computation programs that allowed it to decipher information sketched directly on a computer screen. Sketchpad was valuable in drawing scientific, mechanical, mathematical, electrical and animated drawings.
Sketchpad was a unique system and helped especially in understanding processes like the concept of linkages, which could be explained using pictures. With Sketchpad, it was easier to draw highly accurate and highly repetitive drawings. It also featured the option to edit a previously drawn picture.