All About DXF File Format for 3D Printing
Learn more about the importance and use of this file format.
The DXF (Drawing Exchange Format or Drawing Interchange(X) Format) is among the most common formats for CAD and CAM packages. It is universally supported in 2D and 3D CAD software. But, it is only widely used as an interoperability tool to share models/drawings across incompatible CAD programs. Being a vector system, it reproduces precisely, without the degradation that is common in some formats.
This universal interoperability means that virtually any 2D and 3D CAD viewer, file converter, design package, or CAM machine can handle input data in DXF format and produce a precise interpretation of the original. It is in CAM (Computer Aided Manufacturing) tools that DXF matters most. Many CNC tools use DXF directly to generate the G-code they require as machine instructions.
This article seeks to answer the question “What is a DXF file?” and considers the history, importance, file types, and applications of use.
A DXF file is a CAD format mostly used by engineers, designers, and architects for drawings during product design and manufacturing. It is the first universal 2D CAD format launched by Autodesk in 1982. While DXF can handle 3D files, it is important to remember that it can only work in 3D with data that was saved as 3D DXF. It remains supported by its originator, Autodesk, which regularly releases updates to the open-source code and maintains full backward compatibility.
DXF began as a vector file construction. This means that every element is a product of a mathematical string in a grid space, making it able to display at resolutions only limited by the 16-bit floating point math capability it utilizes. You can zoom in on a DXF file, and the resolution of the view remains unaltered until the zoom limit is reached. It is worth noting that during format conversion, it is very common for the scale/dimension units to be lost. Therefore, when making an STL file, be careful that your model hasn’t become 100 m across rather than 100 mm.
Autodesk created the DXF format structure in 1982. It was designed as the open-source interoperability tool for AutoCAD. Like many players, Autodesk sought to define a standard over which they could retain some control. More than 50 years later, Autodesk is still in control and is constantly releasing updates.
A DXF file can be converted using installed apps and online tools. The steps in converting a DXF file will vary depending on the app and online tool being used. It is recommended to check the specific steps per app/tool before converting a DXF file. For more information, see our guide on how to Convert a DXF File to STL.
Creating a DXF file is the result of a save-as or export action in the range of 3D design, visualization, and rendering packages. Because DXF has such a long history, there are sometimes complications in the ways CAD packages handle the format. However, when saving a file to transfer it to a CNC supplier or a home CAM machine (vinyl cutter, laser engraver, etc.), DXF is a reliable and widely trusted tool.
DXF is one of the formats that allows divergent design tools to communicate for design sharing. It serves as the supplier of precise and reliable information to the full range of CNC and CAM equipment to manufacture products as designed.
DXF files have existed in two formats historically—exclusively ASCII from 1982 to 1988 and binary and ASCII from 1988. Current DXF tools that operate the open-source file structure correctly can handle both types. DXF originated as a drawing format to allow organizations outside Autodesk to use their data without getting proprietary DWG format data. The switch to 3D data enabled the sharing of 3D files as the wider CAD market (and AutoCAD) evolved. Therefore, there are 2D and 3D DXF files, both of which can be utilized by tools that comply with the Autodesk open-source standard.
The best DXF file converters are:
- Bear File Converter: The Bear File Converter is a reliable and easy-to-use tool that will handle DXF to STL conversions for files of 50 MB or less. Bear also handles conversion to DXF well.
- Filestar: The Filestar DXF to STL converter is an installed, lightweight tool that avoids complications. Though it is not widely known, it is well supported and performs its task well.
- FreeCAD: FreeCAD is equipped to perform a wide range of file conversions and, with a little practice, will allow users to do much more than simply converting file formats.
There are many applications that allow more than just viewing and reviewing DXF files. Below are some of the best applications:
- SolidWorks and Solidworks Electrical: SolidWorks is a leading professional design package that puts massive 3D power within easy reach. Icon-driven menus make it easy to learn the basics. The downside is that it is expensive, with an annual fee of $1,295.
- FreeCAD: FreeCAD is a free and modest package that will nonetheless provide powerful design capabilities and allow rapid skill development. It is widely used and well-liked, with a great online community and many free DXF files.
- GrabCAD: GrabCAD is a simple design tool aimed at the home/maker sector—but it is still quite capable in 3D modeling terms, and it's free. The community around GrabCAD is great at file sharing, so there are a lot of free DXF files to explore while learning to use the tool.
Yes, a DXF file is the same as a CAD file in that DXF is a CAD format. However, the DXF file format was specifically created to allow AutoCAD users to provide data to non-AutoCAD users and manufacturers without sending out their “native” DWG data. DXF is not a design format. Design is carried out in one of a wide range of CAD packages with a native format. DXF contains (almost) all of the design data and is widely accepted as a CAD communications tool.
DXF and STL files have several differences. STL 3D printer files store a 3D form as a series of 2D polygons (generally triangles) with standardized X-Y-Z coordinates for the corners. It also has a “unit normal” line of length 1 unit to indicate the outer face. DXF, on the other hand, stores the definitions of edges and curvature as pure mathematical functions. This approach produces a much higher precision interpretation of a 3D shape, however complex. Another difference is that STL will often mishandle the common axes of two polygons and make them coincident but not joined. This results in a file fault that must be repaired. DXF is very precise in the joining of surfaces, as the correlation line between them is defined mathematically—and only once. STL is a simple and lightweight system that generally contains only sufficient data to reproduce a body’s surface. This representation is approximated by a linear and angular resolution (triangle size) that is defined as the file is created. DXF is a much more content-heavy format that describes a part or assembly at very high resolution at all times. Lastly, STL can carry color information in binary format, but this facility is rarely used. DXF applies a color number to each mathematically generated surface, and this information is intrinsic to the file format.
This article provided a review of the DXF file format, including its history, uses, and importance. To learn more about the DXF file format and how you can use it for your projects, contact a Xometry representative.
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