A DXF file or image is a tagged data or vector file representation of an AutoCAD drawing file. DXF stands for Drawing Exchange Format or Drawing Interchange Format. It is identified using the .dxf file extension. Architects, designers, and engineers use the file format for the 3D and 2D drawings during product design.
Various 3D applications support the DXF file format, primarily for sharing design data across CAD programs. DXF files use the .dxf file extension. While the DXF format is an open standard with publicly available specifications, it is not open-source. This distinguishes it from other proprietary formats commonly used in CAD file sharing, such as DWG files.
Compared to other file formats, the DXF format widely focuses on enabling data interoperability between AutoCAD and other programs. DXF format and its closest variant, DWG file format, are industry standards for designers using CAD programs.
History of DXF Files
Autodesk created and launched the DXF format in 1982. Since then, it has become the most widely applicable CAE/CAM/CAD application worldwide. It is quite popular among designers, engineers, and architects because of its compatibility and support for most 3D and 2D formats on PC platforms.
A DXF file is an ASCII file with 2D and 3D modules representing a drawing. The modules are referred to as Entities. The file format can represent all CAD drawings, integrating such entities and connecting a group of entities, including doors or windows, and using them later within the file.
The DXF file format has evolved from version 2.6 to version 14, which are components of AutoCAD 1.0. However, the primary versions of AutoCAD only supported ASCII files of DXF. The release of AutoCAD 10 and above in 1988 enabled it to support both binary DXF files and ASCII.
Initially, Autodesk rarely shared any file format particulars, so importing the correct DXF files took a lot of work. DWG's technical specifications were closely protected as trade secrets. Any CAD programs handling DWG files had to reverse engineer the file or pay Autodesk and sign a non-disclosure agreement.
Nevertheless, creating an open-source file format enabled developers to collaborate with more programs and exchange files with AutoCAD. DXF made it possible to represent every user-specific data in a drawing file. Examples of DXF include FDxf, Dxf12, and Dxf13.
The file format allows for data interchange between AutoCAD and other applications. It enables data to be imported from various formats to DXF and AutoCAD using the DXF file format interoperability specifications.
Properties of DXF Files
The DXF file format comprises tagged data representing each information in the AutoCAD drawing file. Each element in the file is preceded by an integer number known as the group code, having a value indicating the kind of data elements that follow.
Structure
DXF is a vector graphics file format represented by the “.dxf” extension. It organizes the contents into sections using group code and paired values. All sections comprise records, and every record consists of a data item and a group code.
Every value and group code is independent within the DXF file. However, every section begins with a group code 0, closely followed by a sequence, SECTION. The string section is followed by group code 2 and a string denoting the section's name.
All sections are made up of group codes and values defining their elements. The section ends with a “0” followed by the string ENDSEC. A DXF file format considers contents dissimilar from entities. Such contents hardly have any graphical illustration, although entities have.
Entries in a DXF file are called graphical objects, whereas objects are known as non-graphical objects. Its ENTITIES and BLOCK sections have Entities, and group codes used in the two sections are alike. An entity's end is shown by the following 0 group, starting the following entity or indicating the section's end.
The DXF file has a header, classes, tables, blocks, entities (graphical objects), objects (non-graphical), and thumbnail images. The header section often starts in the DXF file. The code is the most crucial variable in the header as it identifies the DWG format version.
The header variables also include the creation and adjustment time and date, project name, coordinate systems used in spatial settings, drawing size limits, drawing styles, and default units. Conversely, the classes contain data relating to application-custom or defined classes whose objects are in other sections.
The tables section has many tables supporting the CAD application's functionality or rendering of drawing content. The styles for text and lines are saved in tables, and then named layers and views are used to control the printing and rendering of the DWG file's 2D and 3D contents.
The blocks section comprises an entry for every block in the CAD drawing. The blocks are called the assembly of graphical entities, and they are used to represent a specific element of the type used recurrently in the design.
The entities (graphical objects) section contains simple entity types including vertex, circle, line, complicated spline, 3Dsolid, polyline, and shape. The entity objects comprise references to associated objects, namely owned and owner objects.
References are made using a string of handles, identifiers, and references to the identifiers following specific syntactical bonds. On the other hand, the objects section (non-graphical) includes settings and dictionaries supporting the rendering and drawing functions in the CAD applications.
The thumbnail image represents an optional section when the preview image is saved for use inside the applications menus or directory listings. A DXF file supports standard rendering. Its files or images can be scaled to any dimension or screen level but retain high image resolutions.
The DXF file format stores colors using the indexed color method. Its color palette defines every possible color a drawing can have. Each object in the drawing codes color using spatial positioning in the color palette instead of its complete color specification.
When rasterized, the DXF's color depth column supports the indexed value representing the color depths of 8-bit and 256 colors. RGB is a 24-bit True Color, and RGBA is a 32-bit True Color. The DXF file has no specific size limit. Nonetheless, its maximum file string length is 256 characters or color channels.
DXF files are high quality due to their wide color support, detailed files, and expansive bit depth. The bit depth of DXF files determines the quality of their images. A DXF file can be scaled indefinitely because the tolerable precision of a floating point in its files extends to a maximum of 16 decimal places.
Designers or technical developers can render DXF images with as high a precision as 0.000000000000000. DXF offers excellent support for vector graphics. Besides, over 60 types of geometric objects are defined and grouped in layers or as blocks.
However, it has limited support for 3D models and 2D drawings but supports geospatial positioning and multiple viewports. A DXF hardly permits multi-sample pixels. Its sections, including entities, tables, and blocks, comprise individual pixels. However, the file format only allows one image per file.
Storage
A DXF stores data as an ASCII or binary representation of drawing files, supporting 2D and 3D data. The ASCII DXF file represents the entire drawing in text form, with data represented by text and numbers that can be interpreted using the specification document. The binary DXF file is smaller, requires less storage, and is faster. ASCII DXF files can be stored and edited in Notepad, while both ASCII and binary DXF files can be stored in AutoCAD, the cloud, file systems, Content Delivery Networks, and hard drives.
Compression
DXF files hardly require lossless or lossy compression. They are an uncompressed file type. All elements and objects in a drawing can be completely described using ASCII text. Compared to bitmap images, DXF images cannot be saved at a lower resolution, and no pixels are omitted.
As a result, complex drawings have no definite sizes and can be rather large. The larger file sizes of DXF file format increase website loading time. However, the binary DXF files are often 25% smaller than ASCII files and can be processed nearly five times faster.
Compared to the ASCII DXF files that involve a trade-off between floating-point accuracy and file size, binary DXF files reserve all of the image accuracies in the drawing file. Thus, all DXF files are of high quality and high resolution because all image data are reserved.
Editing
As it is ASCII-based, the DXF file can be edited using different software and programs, such as CorelCAD, Adobe Illustrator, Scan2CAD, AutoCAD, LibreCAD, Solidworks, QCad, DraftSight, and CorelDraw.
A DXF image can be resized using CorelCAD, DWG FastView, LibreCAD, nanoCAD, FreeCAD, QCAD, RootPro CAD Free, DWGSee, Adobe Illustrator, ASPOSE, Conholdate, ZWCAD, M4 Personal and LibreCAD.
Animation
DXF files do not support animations or standard systems fonts. However, animate supports the AutoCAD DXF format in AutoCAD 10. Animate attempts to map font appropriately, although animation results can be unpredictable, especially text alignments.
Since the DXF file format hardly supports solid fills, the filled regions are exported as outlines only. As a result, the DXF format is ideal for line drawings, including maps and floor plans. The 2D DXF files can be imported into animate, which does not support 3D DXF files.
Transparency
DXF does not support transparency or layer transfer modes. The DXF file format comes in the form of plain text format and can only be viewed and opened using very basic text editing tools.
Most DXF file data elements are specified using numerical codes instead of human-readable element tags, and the documentation for some substructures is insignificant. Thus, the semantics of the drawing content in the DXF file cannot be easily understood.
Best Use Case of DXF Files
- Suitable for storing blueprints, models, and drawings that can be viewed, edited, or modified using different CAD programs. DXF files play an essential role in the engineering and design world.
- They are suitable for 3D printing, laser cutting, and CNC machining because they contain detailed image data and are universally compatible.
Unrecommended Use Cases of DXF Files
- Unsuitable for creating complex web designs or imagery because they are larger and uncompressed.
- Unsuitable for creating CAD-application-specific objects because of its limited features.
DXF Browser Support
Browsers support DXF files include:
- Apple Safari
- 64-bit new Microsoft Edge
- 64-bit Google Chrome
- 64-bit Mozilla Firefox
- Internet Explorer 11
DXF files are supported by browsers such as:
- Opera Mini
- Internet Explorer 10 and below
- Discord
- Brave
- Vivaldi
Possible DXF Browser Errors
The possible browser errors encountered when using DXF image files include:
- Error importing a DXF file
- Import failed for DXF file
- Unable to open DXF files
- Bad file
- The file is corrupted
- The operation cannot be completed because of an unknown error.
Advantages of DXF
- Compatible: DXF files can be easily edited or viewed using most GIS, CNC, and CAD software, including CorelCAD, SolidWorks, Scan2CAD, Adobe Illustrator, and AutoCAD.
- Interchangeability: DXF files are highly compatible, making them a bridge between users and various CAD software. Designs can be shared between new and old software and between colleagues.
- Open-Source: DXF file specifications are publicly available online and accessible by developers and programmers who create CAD software or programs.
- Easily Parsed: DXF files can be quickly processed and divided into small modules that are useful for particular programs. When converted online, the files allow you to remove or keep hatches, fills, or other details.
Disadvantages of DXF
- Limited Features Support: DXF format does not support specific CAD features, including application-specific objects like line widths.
- Complex and Larger Files: DXF is a complex vector file created using the ASCII text standard, making its files larger.
- Limited Support for Application-Specific CAD Elements: AutoCAD dynamic blocks cannot be represented in the DXF file format because specific programs ignore objects attached to them.
- Limited Metadata Support: Compared to some other CAD file formats, DXF files have limited support for rich metadata. This can restrict the amount of additional information that can be stored within the file.
How to open DXF files
DXF files can be opened by CAD programs and software such as AutoCAD, DraftSight, CorelDraw, Adobe Illustrator, Scan2CAD, LibreCAD, DWG FastView, RootPro CAD Free, DWGSee, nanoCAD, FreeCAD, Solidworks, QCad, and SolidWorks.
DXF files are compatible with Mobile Operating Systems (such as Android and iPhone), Windows, Linux, MacOS, Macintosh, and Unix Systems operating systems.
The DXF file format does not inherently support MacOS, Linux, Windows, Mac, or Mobile Operating Systems, including Android and iPhone. Therefore, additional supporting apps must be installed to open and view these files.
Converting DXF
Online DXF converters can convert DXF files to CGM, CMX, DGN, DRW, DWF, DWG, EMIF, GBR, PCL, PCT, PDF, PLT, PD, RTF, SHP, SVG, VEC, VPG, WMF, WMZ, W00, and MIF. Our online converters can also convert your file to other formats.