A list of file extensions and what they are used for and what they mean.
Written by Allan, Jan 2004
This is the standard file format for saving vectors in AutoCAD. It contains the drawing. Older version AutoCAD’s cannot read newer version AutoCAD drawing formats. It is wise not to assume recipients of your drawings have your AutoCAD version.
Drawing Sheet Set data file.
Every time the sheet date file is opened the current sheet set data is copied to a backup file with the extension .ds$. To restore, rename the backup file extension to .dst
This is a backup file of the .dwg file. When you save a named drawing for the first time, AutoCAD creates a backup copy of the drawing using the .bak file name extension. Each time you use SAVE or SAVEAS with the current drawing name, AutoCAD updates the backup file. If your program terminates unexpectedly, AutoCAD tries to rename the backup file to prevent the corrupted file from replacing the existing backup file. AutoCAD renames the backup file with the .bk1 file name extension if that file does not exist. If that backup file exists, AutoCAD generates new file types in the sequence .bk2 to .bk9, .bka to .bkz, .baa to .bzz until it finds a unique file name. If your system fails and the backup file contains the previous version of the drawing file, copy the backup file to a safe place in case you need to revert to that version. To use the backup copy of the drawing, rename the file with a .dwg extension.
This is a drawing template. Introduced in R14, templates contain all the setup parameters for new drawings. They are the same as .dwg files and thus any .dwg can be saved into a .dwt.
This is a Drawing Web Format, and is designed for publishing on the Internet. Introduced in R14, users can view drawings without AutoCAD installed on their computers. The browser plug-in WHIP! Needs to be installed for .dwf viewing. WHIP! Can be downloaded from the AutoCAD web site. It is also installed when Standard AutoCAD is installed onto a computer.
.SV$ .$AC . AC$ .$A
This is an AutoSave. AutoCAD will save the drawing to this file automatically within a set time frame. This is set in the preferences dialog box. AutoCAD can be told where to place these folders. Copy the AutoSave file to a safe place in case you need to revert to that version. To use the AutoSave copy of the drawing, rename the file with a .dwg extension.
This is a Drawing Interchange Format. These file formats AutoCAD uses to interchange drawing data with other applications. DXF files can be either ASCII or binary formats. Because ASCII DXF files are more common than the binary format, the term DXF file is used to refer to ASCII DXF files and the term binary DXF file for the binary format. An ASCII DXF is a full text file version of the drawing. It is not complied, that is there are spaces between the words. A Binary DXF is the same as a ASCII DXF but it is complied. Binary DXF’s are typically 25% smaller that ASCII DXF’s and load about 5 time faster. Please be aware some programs do not read Binary DXF’s. DXF formats can vary from different releases.
The DXF format option produces a subset of the AutoCAD drawing interchange file format containing only block references, attributes, and end-sequence objects. DXF format extraction requires no template. The file extension .dxx distinguishes the output file from normal DXF files.
This is a Windows Meta File and it is in a vector format. These file can be used if you need to use the drawing in a non-CAD program. For example, a Word document. Use the WMFIN or WMFOUT commands to make
This is a slide file. It contains a raster image or snapshot of the display on the graphics screen.
This is a slide file library. It is a collection of slide files organized for convenient retrieval and display. They are created with the slidelib.exe utility.
A windows bitmap image file. To create a .bmp from a drawing use the BMPOUT command
A solid model file output. ACIS provides a solid modeling file format that AutoCAD can use to store solid objects. An AutoCAD solid, a body, or a region can be stored as an SAT (ASCII) file.
The .stl file format is compatible with stereolithography apparatus (SLA). The solid data is transferred to the SLA as a faceted representation of the model. The facets consist of a set of triangles (with outward pointing normals) that approximate the faces of the model. From the faceted data, the SLA workstation produces a set of contours that defines a series of layers representing the part to be built.
A 3D Studio® format.
This is an Encapsulated PostScript.
This is a plot file, and can contain any printer format saved to a file. For example HP-GL/2