CAD file formats are important because not all formats are interchangeable. You can view some CAD files only in specific CAD applications. (To learn about how to convert from one CAD format to another, click here.)
Have you ever worked with CAD? If yes, you’re already likely to be familiar with some of AutoCAD’s most common file format, such as DWG and DXF. These aren’t the only file extensions and formats used with AutoCAD, though. In fact, there are some formats that many people are not entirely familiar with. What is a file format actually? Is a file format different than a file extension? If you are lost with such kinds of questions, this article is for you.
File Extension:
A file extension is a group of characters after a file name, e.g. if there is a file in Windows named ‘article,’ and you find it as ‘article.docx,’ then ‘.docx’, is the file extension. This file extension, ‘.docs’ lets Windows know that which program on your computer the file, ‘article’ can be open with. Here, extension ‘.docx’ should be open with Microsoft Word.
File Format:
Every file in a computer is in a particular type of format. Typically file extensions determine the file format or file type. For example, if you have an extension, ‘.docx’ or ‘.doc,’ you must be dealing with Microsoft Word. Most often, an extension goes with only one type or a more popular file format. For example, the ‘.pdf’ extension means ‘Portable Document Format’. This is the reason the two terms (file extension and file format) are interchangeable.
What Is A CAD File?
CAD is an image file format used by AutoCAD, which is generated by CAD software programs and also creates 2D and 3D designs for models or architecture plans. CAD files hold information for these images; 2D CAD files are often referred to as drawings, whereas 3D files are called models, parts, or assemblies. CAD stands for Computer Aided Design.
Why is CAD File Format Important?
While creating any kind of document using a computer, you must save it as a file. This file contains all the necessary information related to the document as well as the way it one should process or visualize it.
CAD file formats are also extremely important when considering CAD design. When using programs such as AutoCAD or SolidWorks, you are creating a digital document. You then save this document as a specific type of file format.
CAD file format indicates which program will open the document for viewing. It can also give an indication about the content of the document.
Each CAD system has its own method of describing geometry, both mathematically and structurally. CAD files hold information for these processes, as well as drafting information.
As mentioned above, there are 2 dimensional (2D) and 3 dimensional (3D) file formats. As the name suggests, in a 2 dimensional system you are operating with only 2 axes. The resulting file is a layout/draft of the object that you are designing.
In a 3 dimensional (3D) environment the object is more visual as we have added another axis into the system. The objects seem real and curvatures, texture and you can easily view all complex surface features.
Usually we design components in a 3D environment and then we convert them into 2D format prior to the manufacturing stage (“production drawings”). Latest production techniques can work from the 3D data itself (“CAM”, Computer Aided Manufacturing).
Categories of CAD File Formats:
CAD file formatting controls we view the design within a particular program such as AutoCAD or SolidWorks. There are two main categories of CAD file formats:
– Proprietary
– Non-proprietary (or neutral).
Proprietary vs. Non-proprietary
Have you ever heard the terms, ‘proprietary goods’ and ‘non-proprietary goods?’
Proprietary goods are those associated with a particular company whose name is on the product. On the contrary, at its most basic definition, non-proprietary is a generic good type.
What do these two terms mean in the context of CAD file formats?
There are some CAD programs, which use proprietary file formats. These are the file formats that are solely for use with just one CAD software package. This file is generated and coded in such a way that it can only be opened using that particular program. If you try to open a proprietary file in another program, you get an error.
Proprietary CAD file formats contain everything from the original design; nothing will be left out. This type of file is useful for sharing designs within the company and every user must have access to the same program. Hence, in this case a neutral file format is unnecessary.
A neutral or non-proprietary file format is not exclusive to one CAD program. It is considered as vendor neutral and can be opened in different programs that can read it. This type of CAD file format generally uses generic information and standardized protocols so that many programs will understand the contents within.
Non-proprietary or neutral CAD file formats are useful when you need to share the documents with external sources. You may, for example, wish to share a CAD product design with a customer, who has no access to that particular CAD program. If the design is in a non-proprietary format, they are still able to open the file.
Most Popular Proprietary CAD File Formats:
1) SolidWorks
The SolidWorks file format is a proprietary file for the SolidWorks CAD software that runs on Windows systems. This CAD program first appeared in 1995. It is one of the longest-running CAD program and still very popular. SolidWorks is capable of creating both 2D and 3D drawings. The proprietary SolidWorks file format is quite common, but they have also released a popular neutral format as well.
2) Autodesk Inventor
This is another hugely popular designing program and you can use it to create 3D documentation and realistic scale models of parts as well as components. Moreover, this program is compatible with BIM (building information modeling).
3) Solid Edge
The proprietary file format for this program is Solid Edge. The file extensions for this formats are ASM, PAR, PASM, and PWD.
Some Popular Neutral File Formats:
1) STEP
STEP is one of the most widely used CAD file formats. This format is created in conjunction with ISO 10303. ISO 10303 is the standard for computer representations of product manufacturing information. Most modern CAD software supports this file format. STEP can support both single file and assembly formats. It also can contain a Bill of Materials (BOM).
2) VRML (Virtual Reality Modeling Language)
This type of non-proprietary file format is useful for the representation of 3D graphics and interactive vector graphics. The VRML file format is useful for web graphics, which can specify surface color, textures, transparency, and other important graphical concepts.
VRML and its successor X3D have become international standards (ISO). This format emerged in 1994. X3D was approved later on in 2005. Both file formats are non-proprietary and can be opened with a variety of programs.
3) IGES
IGES (pronounced as eye-jess) is another popular non-proprietary format. This format was first developed in 1980 and widely used in the CAD industry since then. It is developed exclusively by the US Airforce, but once they started to use other technology, the format was taken over by ANSI.
This file format is used to display wireframes and circuit diagrams. Because of its lack of color rendering and textures, it should generally not be used to share designs with third-party organizations, unless they know the design process or the product.
AutoCAD’s Common File Types: DWG and DXF
DWG:
DWG is used as an abbreviation for ‘Drawing,’ which is a proprietary vector file format of Autodesk (1982). Developers need a license to access this format in their software. DWG files are smaller than DXF files due to their binary makeup. Users can view and edit DWG files with other programs too, including Scan2CAD, though they are designed to be used in AutoCAD.
DXF:
Drawing Exchange Format, DXF, is a vector file format and was created by Autodesk as an exchange medium between different types of CAD software. It is an open standard, so it’s supported by practically every CAD program in the market. You can also view DXF files using a range of programs including Adobe Illustrator and Scan2CAD. While DXFs are smaller than their raster counterparts, they’re typically larger than DWGs. Why? Because DXFs are made up of ASCII text, whereas DWGs are binary.
Some More File Formats for Sharing 2D and 3D CAD Designs:
STL:
Stereo Lithography is a universal format. It is a format for pure 3D information that has been specifically created by 3D programs. STL is concerned with surface geometry and shapes. You cannot use it to represent color or textures. This file format is fine for use in basic situations.
X3D:
X3D actually replaces the non-proprietary file format of VRML. Although VRML was popular, it was limited to only a number of different software packages. X3D is also a neutral file format and is used to represent 3D computer graphics in an XML format. It can be used to encode graphical scenes with the XML syntax, and it allows integration with a number of different APIs as well.
PDF:
The Portable Document Format is proprietary to Adobe but has a wide array of uses. You can convert PDF files into AutoCAD files, but if the PDF is just a bitmap, you will need to vectorize the image using either auto-vectorization software or (better) by manually tracing over the drawing using your CAD software (auto-vectorization is still not good enough for most applications). CAD files can also be exported into PDFs for easy viewing. If you want to simply showcase a 2D design to a customer or someone without CAD knowledge, a PDF file is suitable. Many CAD programs allow you to export your work to a PDF.
Some File Extensions That Are Developed For and Associated With AutoCAD
1. CAD Standards File:
• DIM — Exported Dimension Style file (DIMEX/DIMIM commands).
• LAS — Exported Layer State file (LAYERSTATE command).
• LIN — Linetype file (LINETYPE command).
• MLN — Multiline Style file (MLINE command).
• NFL — Custom Filters file (FILTER command).
• PAT — Hatch Pattern file (HATCH command).
2. Customization Files:
a) Tool Palette-Related
• ATC — Tool Palette Catalog file.
• XTP — Exported Tool Palette file (CUSTOMIZE command).
• CUIx — Customization file (CUI command).
• DBX — ObjectDBX file.
b) Library-Related
• CBL — Content Browser Library file.
• DLL — Menu Resource Library or .NET Assembly.
• SLB — Slide Library file.
• SLD — Slide file (MSLIDE command).
c) Auto LISP-Related
• FAS — Fast-load AutoLISP file.
• LSP — AutoLISP Source file.
• MNL — Menu LISP files.
• VLX — Compile AutoLISP project file (VLIDE command).
• DCL — Dialog Control Language file.
• DCE — Dialog Error Log file.
d) Shape-Related
• SHP — Source Shape file (SHAPE command).
• SHX — Compiled Shape file (COMPILE command).
e) Various
• ACTM — Action Macro file (ACTRECORD command).
• ARX — ObjectARX file.
• BMP — Bitmap file (BMPOUT command).
• DVB — VBA Project file (VBAIDE command).
• PGP — Program Parameters.
• SCR — Script file (SCRIPT command).
3. Drawing Files:
• DST — Drawing Sheet Set file (SHEETSET command).
• DS$ — Autosave.
• DWF — Drawing Web file.
• DWS — Drawing Standards file.
• CHX — Batch Standards Checker file.
• DWT — Drawing Template file.
• DXB — Drawing Interchange Binary file.
4. Plotting Files:
• DSD — Publish Set file (PUBLISH command).
• PC3 — Plot Configuration files.
• PLT — Plot file.
• PSS — Plot Stamp Settings file (PLOTSTAMP command).
• PTW — Publish to Web Template file (PUBLISHTOWEB command).
• CTB — Color-dependent Plot Style file (PLOTSTYLE command).
5. Rendering Files:
• ADSKLIB — Materials Library file (MATBROWSEROPEN command).
• IES — Illuminating Engineering Society file (WEBLIGHT command).
The above list shows a few file extensions that you may run into, but it’s a truism that “there are more CAD file formats than there are CAD design programs!”
Which Type of File Format should be used?
Now, the obvious question comes to mind is, which type of file format should you use? The file format you should choose largely depends on the type of CAD program you’re using. You may have to use a proprietary file format. For example, you may want to work exclusively with SolidWorks, which is a proprietary format. Or you could use non-proprietary formats such as STEP.
We have experts who can convert CAD files from any format to any other format, and we offer a free trial of our service. If you’re looking for help in converting a CAD file, send it to us and we’ll be happy to assist you. For a free trial conversion (limit of one per customer), mention the following discount code: CAD-File-Format-Free.
Also, if you need help in converting from an image file (e.g PDF, PNG, TIF) to CAD (e.g. DWG), click here.
If you would like to convert from PDF to DWG via our free online conversion service, click here. You will find a special discount code on this page.
Curious about diving deeper into the world of CAD? Here are some topics to explore:
Gain comprehensive insights into the fundamentals and advanced aspects of CAD.
Discover tools and frameworks that streamline the software development process for CAD applications.
Understand how CAD systems maintain relationships between designs and ensure changes are updated automatically.
Learn how to efficiently import and integrate various design files into your CAD software.
Explore the techniques used to transform and manipulate digital models within CAD environments.
Check out these topics to expand your knowledge and enhance your CAD skills!
Leave a Reply