DWG is a proprietary file format primarily used to store two- and three-dimensional design data created in AutoCAD, the flagship computer-aided design (CAD) software from Autodesk. Opening these files typically requires software that understands the complex structure of DWG. However, you don't need the full AutoCAD application itself. Several alternatives exist, including free DWG viewers offered by Autodesk and other companies, as well as less expensive CAD programs or even open-source CAD solutions capable of interpreting or converting the format. These solutions provide access for viewing, printing, and sometimes basic measurements without the entire AutoCAD feature set or cost.

In practice, designers, architects, and engineers commonly use free viewers like Autodesk's own DWG TrueView or online Autodesk Viewer to share and review DWG drawings with clients or contractors in construction and manufacturing. Non-AutoCAD CAD software, such as BricsCAD, ZWCAD, or free tools like LibreCAD/DraftSight (often by first converting DWG to the open DXF format), allows users needing more than just viewing – like markup or simple edits – to work with DWG files without purchasing AutoCAD licenses for every user.

A key advantage is significant cost savings, especially for individuals or businesses with infrequent needs. Limitations include potential loss of fidelity when converting formats, missing specialized objects (like dynamic blocks or custom entities unique to newer AutoCAD versions), and reduced editing capabilities compared to the full AutoCAD suite. The proprietary nature of DWG has ethical implications regarding data accessibility long-term, driving efforts towards more open formats like DXF or vendors developing robust interoperability standards to ensure file accessibility regardless of platform.