CAD Overlay CAD Overlay CAD Overlay is a commercial software application for raster-to-vector translation in 2D computer-aided design (CAD) and drafting — available between 1988 and 1996 as a third-party application for AutoCAD and other CAD systems. Developed and marketed by Image Systems Technology, CAD Overlay was first released in January 1988 running on AutoCAD Version 2.6. CAD Overlay replaced the previous generation of automatic raster-to-vector translation systems by embedding scanned documents and images directly in the CAD system. CAD Overlay was derived from a custom AutoCAD application developed using the Nth Engine graphics board in 1987 by David Chassin for Image
Computer-assisted language learning (e.g. repeating, paraphrasing, slowing down, correcting, or directing the student to background explanations)." Jones C. (1986), on the other hand, rejected the idea of the computer being "some kind of inferior teacher-substitute" and proposed a methodology that focused more on what teachers could do with computer programs rather than what computer programs could do on their own: "in other words, treating the computer as they would any other classroom aid". Warschauer's high expectations in 1996 have still not been fulfilled, and currently there is an increasing tendency for teachers to go down the route proposed by Jones, making use of