Shaded Picture System

The Shaded Picture System was a 3D raster computer display processor introduced by Evans & Sutherland in October 1973.^[1]

Shaded Picture System

Manufacturer	Evans & Sutherland Computer Corp.
Type	computer graphics terminal and 3D display processor
Release date	October 1973; 51 years ago
Display	256 by 256
Graphics	raster, black and white

The Shaded Picture System was the first general-purpose, commercially available raster computer graphics display processor capable of real-time, shaded 3D graphics. It could only display black and white graphics at a resolution of 256 by 256.^[2] It was extremely expensive, and very few units were ever sold.^[3]

History

An image of a cube generated by the first algorithm at the University of Utah in 1967.

A color image of a church generated by the FORTRAN simulator of the Watkins algorithm at the University of Utah in 1970.

The principles of shaded, hidden-line true 3D graphics were pioneered at the University of Utah in 1967.^[4] However, this algorithm was slow and would take several minutes to produce an image. In 1970, Gary Watkins developed a FORTRAN simulator of a faster algorithm that would theoretically generate shaded 3D images in real-time, "if implemented in suitable hardware".^[5][2] The simulator itself was still not capable of real-time shaded 3D image rendering. Evans & Sutherland developed a functional prototype of this "suitable hardware", which was later sold as the Shaded Picture System in 1973.^[2]

About a year earlier in 1972, Evans & Sutherland sold the first and only CT1 to Case Western Reserve University.^[6] The CT1, or Continuous Tone 1, was a specialized image generator, not meant as a marketable or mass-produced product. At the time, the CT1, along with G.E./NASA's upgraded Electronic Scene Generator from 1971,^[7] would have been the only real-time raster graphics systems sold to customers comparable to the Shaded Picture System, although both the CT1 and Electronic Scene Generator were intentionally produced as one-off products and specialized for the needs of their customers.^[6] The Shaded Picture System, in contrast, was intentionally marketed.^[2]

An image of a Klein bottle generated by an E&S Picture System (left) and displayed shaded and in color on the frame buffer (right) in 1975.

In early 1975, Evans & Sutherland demonstrated a random-access video frame buffer using relatively low-cost semiconductor memory, which was much more capable than the Shaded Picture System.^[8] When interfaced with a (non-shaded) E&S Picture System, the frame buffer had a resolution of 512 by 512 in grayscale and partial color capabilities. By the end of 1975, this frame buffer was commercially available.^[9]

See also

• LDS-1 (Line Drawing System-1)