Every file in a computer is created as a particular type or
format. For example, a Corel WordPerfect letter file
is created as a WPD file. A standard AutoCAD drawing
is created as a DWG file. The difference is the way that
the application program recognizes the file. Each file type also has a distinct structure so that the program that created it can read it correctly.
In the ‘olden' days when DOS was the common operating system,
all files had a maximum of 8 characters in their name,
followed by a period, followed by the extension. The
extension was a 3-letter ‘code' indicating the type of
file.
Example: DRAWING1.DWG |
DRAWING1 |
name of the file |
DWG |
extension |
After the introduction of Windows 95, you may have
more than 8 characters in a name (up to 256), but the
3-letter extension remains. Windows is even set up to
hide these extensions from you in its default configuration, so you'll want to turn them on to make things easier for you..
While working with AutoCAD, it is important to know that there
are several types of drawing files. Here are some of
the common filetypes you will come across:
DWG - BAK - DWT - DWF -SV$ - DXF - WMF - 3DS - JPG
These are only a few of the file types that AutoCAD uses. There
are many others that would be considered support files.
Those listed above deal with various forms of drawing
files. There are many other ways to save your drawing,
but these are the common ones.
DWG – This is the standard AutoCAD drawing file format. The thing
to remember is that older versions of AutoCAD cannot
read files created on newer versions. The newest version
can read any of the older files. If you are exchanging
files with other companies, do not assume that they are
using the same version you are. Some co-workers will also have older or newer versions than the one on your computer.
BAK – This is AutoCAD's backup file format. Whenever you save a
drawing, AutoCAD will automatically create a duplicate
backup file. This file has all the same information as
the original, but a different extension. If your original
file becomes corrupt, or unusable for any reason, you
can rename the BAK file to a DWG file and open it as
you would any other drawing file. You can set the interval for backing up your file in the Options > Open and Save tab set for as short as possible with interrupting your workflow.
DWT – This is a newer format (R14) that is used for drawing templates.
Templates are the same as prototype drawings in that
they contain all the setup parameters for certain types
of drawings. They are essentially the same as a DWG file.
DWF – This is also a fairly new format. This is used when you want to create
a drawing that is for use on the Internet or otherwise not editable. It is a Drawing
Web Format. This type of file contains features that
allow users to view drawings on the Web without having
AutoCAD on their computer. You can also use the DWFOUT command to open the Plot dialog box pre-set to DWF setting.
SV$ -
This is AutoCAD's format it uses whenever it performs
an automatic save. AutoCAD will save the file automatically
within a pre-determined time frame. This is set in your
Options > Files dialog box. You can also tell AutoCAD where
you want your autosave files to go. Most computers are
set to save to the Windows/Temp folder. If you need to
recover a drawing from the autosave file, just rename
it to a DWG format.
DXF – This is not really an AutoCAD format but an industry standard, but one that you should
be aware of. DXF stands for Drawing
eXchange Format. This
is a very standard format that is used but many different
CAD and graphics programs. This allows users to exchange
drawings even if they don't have the same program. When
you use the DXF format, some objects may change their
appearance when re-opened. As with DWG formats, DXF formats
vary from different releases. You have the option of
saving the files as a DXF or you can use the DXFOUT command,
conversely DXF Files can be imported using the DXFIN command.
WMF – This is a Windows Meta File. This file can be used if you
need to use this drawing in a non-CAD program. For example,
you may need to add a drawing of section of a drawing
to a Microsoft Word document. You would use this format
to do that. You can export only a portion of your drawing
with the WMFOUT command.
3DS - This is an older extension for 3D
Studio Max - a high level animation and rendering program.
You can import to (but not export from) AutoCAD by using the 3DSIN command.
JPG - Most people know JPG's as the common
format on the internet for images. You can also export your
drawing easily to a JPG now. Use the JPGOUT command and then
choose between the viewport or selected objects. You may need to change your background color to white for this.
BMP - This is similar to
a JPG, but exports a raster BMP file instead of a JPG. Use
the BMPOUT command.
Generally JPG's are smaller and better for e-mail and websites.
PDF - Although not a AutoCAD specific file format, you can now save your drawing as a PDF (Portable Document Format) so that others can read it with the common Adobe Acrobat Reader. Use the Saveas... PDF option.
These are the common file types used in
AutoCAD. The main thing to remember is that you have the
option of sharing your drawing with people who don't have
AutoCAD installed on their machines.
|
RETURN
TO THE TOP OF THE LESSON