AutoCAD

AutoCAD is a commercial computer-aided design (CAD) application developed by Autodesk and first released in the early 1980s. It is used to produce precise two-dimensional drawings and three-dimensional models for architecture, civil and mechanical engineering, electrical schematics, and many other technical fields. Geometry is constructed from primitive entities such as lines, arcs, circles, polylines and text, organised onto named layers that control colour, line type and visibility. Drawings are drawn at full scale in model space and then arranged for plotting in paper-space layouts.

The program is closely associated with its native file formats. The DWG format stores the drawing database itself, while DXF (Drawing Exchange Format) is a documented text or binary format intended for exchanging data between CAD programs. Because so many tools read and write these formats, DWG and DXF have become de facto standards for sharing 2D and 3D vector geometry across the industry.

AutoCAD is highly extensible. Users can automate repetitive work and add commands through several programming interfaces, including the AutoLISP dialect of the Lisp language (with compiled VLX files), Visual Basic for Applications (VBA), and the C++ ObjectARX (ARX) developer kit. Lighter editions such as AutoCAD LT omit some 3D and customisation features. Many alternative CAD systems exist — among them MicroStation, TurboCAD, DataCAD, Vectorworks, CATIA and Siemens NX (formerly Unigraphics) — and interoperability between them usually relies on shared formats like DXF, IGES or STEP.

Frequently asked questions

What is the difference between DWG and DXF?

DWG is AutoCAD's native binary drawing format. DXF is a published interchange format meant to move drawing data between different CAD programs more reliably.

What is AutoLISP used for?

AutoLISP is a Lisp dialect built into AutoCAD for scripting custom commands and automating repetitive drawing and editing tasks.

How does AutoCAD LT differ from full AutoCAD?

AutoCAD LT is a lower-cost edition focused on 2D drafting. It lacks much of the 3D modelling and programming customisation found in the full version.