Initially for mechanical engineers, it has been extended and is very widely used by architects and other design professionals. Its file formats (DWG and its ASCII equivalent, AutoCAD DXF) have become the default standard for CAD packages.
Version 1.0 was released in December 1982. The current version is AutoCAD 2004, which was released in March 2003. A lower-cost version, AutoCAD LT (pronounced "ell tee", not "lite"), was first introduced in 1993. Compared with its more expensive sibling, LT lacks the AutoLISP programming language and other programming interfaces, some 3D capability, and a few other features.