What Is DWG and How Do You Open, Edit, and Convert DWG Files?
DWG is the native drawing file format for AutoCAD and several other CAD programs. It stores 2D (and in some tools 3D) geometry, layers, blocks, text, dimensions, hatches, and other drawing data in a single file. You can open, edit, and convert DWG files with a range of CAD applications, including free and open-source options such as QCAD, which lists DXF and DWG input and output among its main features. The catch is compatibility: DWG is a proprietary format that has changed across versions, so the tool you choose needs to support the specific DWG version your file was saved in.
DWG vs DXF: what's the difference?
Both are CAD drawing formats, but they play different roles:
| DWG | DXF | |
|---|---|---|
| Origin | Native format of AutoCAD and compatible CAD systems | Drawing Exchange Format, designed for interchange between programs |
| Typical use | Primary working file in AutoCAD-based workflows | Sharing drawings between different CAD applications |
| Support in QCAD | Listed as input and output | Listed as input and output |
In practice, DXF is often the safer choice when moving a drawing between unrelated programs, while DWG is what you'll receive from colleagues, clients, or suppliers working in AutoCAD. QCAD supports both, so you can open either and save to either.
How to open a DWG file
- Install a CAD application that supports DWG. QCAD is a free, open-source 2D CAD system for Windows, macOS, and Linux, and it lists DWG input among its features.
- Launch the program and use its open command to select the .dwg file.
- If the file was created in a newer DWG version than your software supports, the open may fail or elements may be missing — see the troubleshooting section below.
- Once open, the drawing appears in the model space with its layers, blocks, and entities intact, assuming the version is supported.
QCAD's main features include layers, blocks (grouping), 35 included CAD fonts, TrueType font support, and both metric and imperial units, so a DWG drawing that uses these standard elements should display and remain editable.
How to edit or create DWG drawings
QCAD is a 2D CAD system, so editing is focused on two-dimensional drafting: plans for buildings, interiors, mechanical parts, schematics, and diagrams. Its feature list includes over 40 construction tools and over 20 modification tools, covering points, lines, arcs, circles, ellipses, splines, polylines, texts, dimensions, hatches, fills, and raster images.
A typical edit workflow:
- Open the DWG file.
- Use entity selection tools and object snaps to target the geometry you want to change.
- Apply modification tools (move, copy, rotate, trim, and similar operations) to adjust the drawing.
- Add or edit dimensions, text, and hatches as needed.
- Save the result back to DWG, or save as DXF if the next program in the chain prefers it.
QCAD also includes measuring tools and a part library with over 4,800 CAD parts, which is useful when you need to insert standard components rather than draw them from scratch. For repetitive or scripted work, it exposes an ECMAScript (JavaScript) scripting interface.
How to convert DWG to other formats
QCAD ships command line tools for conversion, listed as dwg2pdf, dwg2svg, dwg2bmp, and others. These let you turn a DWG into a PDF, an SVG vector graphic, or a raster image without opening the graphical interface — convenient for batch jobs or automated pipelines.
Common conversion targets and why you'd pick them:
- DWG → DXF: when the receiving program handles DXF more reliably than DWG.
- DWG → PDF: for printing, archiving, or sending a non-editable copy. QCAD supports printing to scale and printing on multiple pages.
- DWG → SVG: when you need scalable vector output for web or documentation use.
- DWG → BMP or other raster: when you need a flat image for a report or presentation.
If you're converting inside the application rather than via the command line, the same principle applies: open the DWG, then use the save-as or export option for your target format.
Troubleshooting DWG compatibility and version issues
Most DWG problems come down to version mismatch or unsupported content:
- The file won't open at all. The DWG was likely saved in a version newer than your software supports. Try opening it in a newer CAD tool and saving it down to an older DWG or to DXF, then reopen.
- Some elements are missing or look wrong. Certain entities, fonts, or proxy objects may not translate between programs. Check whether the drawing relies on custom fonts or third-party objects; QCAD's included CAD fonts and TrueType support cover standard text, but not every proprietary object.
- Dimensions or hatches shift. These are often the first things to break across formats. Compare the converted file against the original before relying on it.
- You need a guaranteed round trip. If both ends of the workflow can use DXF, converting to DXF early often avoids DWG version friction entirely.
Choosing a tool for DWG work
QCAD is a reasonable fit if your work is 2D drafting and you want a free, open-source option that runs on Windows, macOS, and Linux and handles both DXF and DWG. It's designed to be approachable — the project states you don't need prior CAD experience to get started — while still offering a deep toolset for technical drawing.
If your work is 3D, or depends heavily on AutoCAD-specific objects, you'll likely need software built around those requirements. For straightforward 2D drawings, opening, editing, and converting DWG files is well within reach of a free tool.