The secret world of file formats

No matter the communication protocol used to transmit it, most information gets packaged into a file format for consumption. File formats are like virtual checkpoints along the information superhighway, and we would do well to pay attention to who is manning the gates.

We’ve heard a lot of noise lately about the need for “open” file formats, but documenting a file format is not the same thing as relinquishing control of the format. The key consideration is who decides when and how the file format changes. This is a dirty little secret about file formats that you are not supposed to know. By controlling when and how a file format changes, an organization can maintain a mindshare monopoly over consumers of its file format — even when the format is “open”.

It may be that the relative anarchy of the internet has given us a false sense of security. We happily use “open” formats like PDF, DWF, DXF, HTM, and others with relatively little concern about who controls them, but all of those formats (HTM perhaps to a lesser degree) are controlled by corporations whose allegiance is first and foremost to their shareholders. For example, PDF is “open”, but did you know that third party developers need a digital ID signed by Adobe in order to create forms-enabled PDF files that can be opened in the free Acrobat Reader?

In April of 2006, Autodesk filed a trademark application for the word “DWG” when used to refer to DWG files. This may seem benign on the surface, but if successful it will give Autodesk more legal leverage in “defending” the file format. A few weeks ago, Autodesk filed a trademark infringement lawsuit against the Open Design Alliance claiming that the ODA infringed their “AUTODESK” trademark by embedding the mark inside DWG files created with its DWGdirect libraries.

Much has been written by the pundits about the pros and cons of the ODA lawsuit, and the Electronic Frontier Foundation predictably suggests that Autodesk is using trademark claims to stymie interoperability, but the bottom line is that the contention centers around a file format — a file format that Autodesk considers valuable enough to wage war over.

Does Vista really open DWF files?

Not according to the press release. Vista (and .NET 3.0) includes a built-in XPS Viewer (also available for Windows XP SP2 and Windows Server 2003), which will view any XPS format file. Apparently Autodesk plans to add support for output to XPS format in the future, and this output will be called DWFx — a new file format. It’s not clear what the difference will be between DWFx and the output produced using the Microsoft XPS Document Writer that is already available.

I installed the Microsoft XPS Document Writer and XPS Viewer on my Windows XP SP2 machine. Next, I started AutoCAD 2007 and opened “3D House.dwg” from the Sample folder. I then plotted this file to DWF, PDF, and XPS, with the following results:

Plotter Plot Time File Size
DWF6 ePlot.pc3 7 seconds 139 kb
DWG To PDF.pc3 5 seconds 165 kb
Microsoft XPS Document Writer 34 seconds 829 kb

I’m not suggesting that these files all contain the same content, I’m merely suggesting that DWFx/XPS may have some undesirable tradeoffs in practice.

This whole issue about “native Vista support for DWF” may be nothing but smoke and mirrors. There is no guarantee that publishing CAD data in the XPS format will be efficient. So what will happen if users can choose between a compact DWF, a slightly less compact but ubiquitous PDF, or a very space-hungry DWFx? Time will tell, but I think this issue of DWF in Vista is getting way to much spin and not enough critical analysis.

Do you use protection?

If you were at AU this year, you may have seen some of my take5 and AUGI friends wearing blue T-shirts with this tag line on the back. This year my CADLock compatriots (Dietmar Rudolph of Germany and Steve Johnson of Australia) were both at AU, so we decided to have a little fun with this protection theme. We brought some “protection” to go along with the shirts (no, those little matchbooks did not contain matches).

Now that you’re back home, I hope you’ll take a few minutes to learn how to protect your AutoCAD drawings. You can download CADVault for AutoCAD from the CADLock web site and run it in fully functional evaluation mode to see for yourself how CADVault can securely lock your AutoCAD drawing content.

Help fight IP theft: practice safe CAD!