.DWG
AutoCAD Drawing
Introduction
DWG is the native drawing format of AutoCAD, which Autodesk first released in 1982. It holds two and three dimensional drawings for architecture, engineering and manufacturing: lines, arcs, text, dimensions, blocks, layers and layouts for printing. It is one of the most widely used CAD formats.
Autodesk does not publish the format. Other programs read and write it using libraries built by studying the files, such as the Open Design Alliance’s SDK and the free LibreDWG.
Software
- AutoCAD (Windows, macOS)
- Autodesk viewers, including DWG TrueView (Windows, web)
- BricsCAD (Windows, macOS, Linux)
- Open Design Alliance (libraries for developers)
- LibreDWG (free library and tools)
Structure
A DWG file starts with six ASCII characters that name the format version. The layout after them differs between versions, and recent versions compress and encode most sections.
| Version string | Written by |
|---|---|
AC1015 | AutoCAD 2000, 2000i and 2002 |
AC1018 | AutoCAD 2004 to 2006 |
AC1021 | AutoCAD 2007 to 2009 |
AC1024 | AutoCAD 2010 to 2012 |
AC1027 | AutoCAD 2013 to 2017 |
AC1032 | AutoCAD 2018 and later |