Edit Proof Your Autocad Drawings

So you want to "lock" a drawing so that other users can view, but not modify, the information in the drawing. Here are a few tips and tricks straight from Autodesk.

There are several ways to prevent drawing data from being modified. You should decide which approach to use based on your situation.

The following descriptions summarize several of these options:

Password protection

AutoCAD® 2004 based programs have a Password Protection feature, which may be accessed for the current drawing using either of the following methods:

In the Options dialog box, Open and Save tab, click the Security Options button.
On the command line, enter securityoptions.
These commands bring up the Security Options dialog box. By entering a password on the Password tab, you may add, change, or remove a password which will be required to open the drawing once the drawing has been saved. If you add or change the password, the Confirm Password dialog box is displayed.

Note: If you lose the password, it will not be recoverable. Before you add a password, Autodesk Product Support recommends that you create a backup of the file that is not protected with a password and save it in a secure location.

In AutoCAD 2000, 2000i, and 2002 based products and AutoCAD LT releases 2000 through 2004, you may use an add-on utility to password-protect a drawing. Search the Internet for such utilities.

Drawing conversion

You can convert a drawing into another file format so it is more difficult to modify. By using an alternative to the drawing file format (DWG) you can maintain some control over the drawing data. You can convert a drawing to one of the following file formats. Note that all of these formats are two-dimensional in nature; thus, some information is lost in the conversion.

EXPORT command. Formats available with the EXPORT command are EPS, BMP, and WMF. These formats are viewable by many graphics software packages. There are, however, conversion programs that can convert these formats back into AutoCAD DXF
™ format so it's not really that secure.

Note: The Export options in AutoCAD LT are more limited than AutoCAD. When using AutoCAD LT, you can choose only the WMF format.


Plot files. Plot file formats such as HP-GL, HP-GL/2, PostScript all provide a good degree of accuracy, and viewing programs are available (search AutoCAD-related Web sites). The PostScript plot file can be converted into the Adobe PDF file format, which is readable and plottable by the Adobe Acrobat program. Also AutoCAD includes the Raster File Export plotter driver, which uses the PLOT command to generate files in several raster file formats (BMP, TGA, PCX, and TIFF).

As with the file formats provided by the EXPORT command, there are conversion programs that can convert these plot file formats back to the AutoCAD DXF format.


COPYCLIP. You can use the COPYCLIP command to take a snapshot of the drawing. Using the PASTE SPECIAL command, you can paste the snapshot in bitmap (BMP) or metafile (WMF) format into another document. The visual accuracy is not as good as some of the other options. The advantage of using this option is that it may be faster than other methods for providing multiple clips of various views of a drawing at various zoom magnifications with accompanying annotation. The COPYCLIP command is limited to the Microsoft Windows operating systems, therefore, the data may not be portable to other operating systems, such as UNIX.
Slide file format. You can use the MSLIDE command to create a snapshot of the current view of the drawing in AutoCAD slide file format. The resulting file can be viewed but not edited in AutoCAD 2000 (using the VSLIDE (command) and other CAD viewing programs.

Hard copy. With scanner and raster-to-vector conversion software, printed media can be converted back into electronic DXF or DWG data. However, you can apply notations or a screened pattern as an overlay to printed media, making it more difficult to convert a hardcopy drawing into electronic format and more time-consuming to edit into a usable drawing.
Design Web Format™ (DWF™), a raster/vector file created from the Plot dialog box using the DWF plot drivers, is the most visually accurate and provides more protection than the other formats. To view a DWF file, you use a DWF viewer, such as WHIP!, which is available free at www.autodesk.com/whip, or others that you can find by searching the Internet.


Drawing alteration

You can modify a drawing so that other users have difficulty modifying it. This is probably the easiest and cheapest way to "secure" a document since you wouldn't need an extra program to do it. For example, locking layers or blocking the drawing data in a nested fashion at various unequal scale factors may impede inexperienced AutoCAD users. However, experienced users would be able to identify and readjust the parameters of such a drawing.

Read-only access

By changing the file attribute of a drawing or setting modification restrictions to certain groups on a network, you can prevent users from modifying drawing data. All viewing operations are available, but the user cannot save changes back to the drawing file. However, read-only access is not a foolproof protection of drawing data. If the drawing file attribute is set to read-only, the user can still save the drawing under a different file name. In a network environment, if the user has access to a directory for writing (such as a disk drive), the user can save the drawing to that location and then modify it.

View-only software

You can provide view-only and redline software to work with the drawing. Several software programs are available that allow a user to view and redline AutoCAD 2000 drawings. These programs have features that allow the user to zoom in and out of the drawing, and view non-graphical information such as layer and block information. One such program is Autodesk View, which is described in detail at http://www.autodesk.com/view. In a controlled environment, this software may provide an effective solution to protecting drawings.

Coverting to PDF

So far my favorite method is converting drawings to PDF. This is the most secure so far and the best way to preserve viewability. There is an extra cost involved though with getting the program to be able to do it. Your typical free Adobe Acrobat Reader may help you view PDF files but it will not make you convert files to PDF. For that you will need the other members of the Adobe family of software products.

The full Adobe Acrobat® product (not Acrobat Reader®) comes with two Windows® system drivers that can be used to create Portable Document Format (PDF) files from AutoCAD® drawings: Acrobat PDFWriter® or Acrobat Distiller®.

Acrobat PDFWriter.
This Windows-based system driver directly creates PDF files and will give the best results with most drawings.

Note: The Acrobat PDFWriter driver is not installed with a typical installation of Adobe Acrobat. To install the Acrobat PDFWriter system driver during the installation of Adobe Acrobat, choose a custom installation and select the Adobe PDFWriter check box.


Acrobat Distiller.
This Windows-based system driver can be configured to create either PostScript (EPS) files or PDF files. If EPS files are created, Acrobat Distiller can be configured to automatically convert the EPS files into PDF files. This driver should be used only with simple drawings. For most AutoCAD drawings, better output is achieved with Acrobat PDFWriter.
Refer to the documentation provided with Adobe Acrobat and in the Adobe Support Knowledgebase for specific information about installation and configuration of these drivers.

Configuring a custom page size

The default page size for Acrobat PDFWriter and Acrobat Distiller is 8.5 x 11 inches. The available default page sizes are for smaller sheet sizes only. You can configure the page size by following your Adobe manual or if you're more savvy you'll be able to use or write an autocad script to automate the page setups for you.