AutoCAD Feature

Intellectual Property Rights

You own the data - but will you always be able to access it?

By Joe Croser & Robert Downing, May 7, 2003

There are only two things in life said to be a certainty - death and taxes. Why then do most of us simply assume that the CAD data we create in applications now will be accessible by us at any time in the future?

Autodesk has recently launched AutoCAD 2004, which has a new file format with compression and the ability to password protect the data inside. It is also alleged by The OpenDWG Alliance that the 2004 files are encrypted, thus restricting the existing user base to authorized Autodesk product use only. Naturally, Autodesk has hotly contested these allegations, which are in direct contradiction with the company's current marketing message “Share with ease.”  [See "Autodesk Responds to the OpenDWG Alliance" below.]

Autodesk Responds to the OpenDWG Alliance

To clarify its reasons for making changes to the file format, and to elucidate the differences between encoding and encryption, Autodesk has issued this response:

The statement issued by the OpenDWG Alliance contains many errors. Autodesk has not and never has encrypted the DWG file format. The folks at OpenDWG have just not figured out how to fully reverse-engineer it, yet. Other companies, such as Cimmetry, have figured out the new format, and are already shipping new products based on it.  Evan Yares of OpenDWG, in his article, "AutoVue Supports AutoCAD 2004," has recognized this, stating, "Cimmetry proved me wrong."

The DWG format was changed to benefit customers by making them more productive with significant new AutoCAD features and functionality. The only encryption in the AutoCAD 2004 DWG is file password protection, which is totally under the control of the user and is there to allow for secure transmission of drawings solely at the user's discretion.

Autodesk does not hide that there is some "encoding" (not "encryption") in the DWG file. There is a big difference between the two. Encoding, when used in a software development context, typically means translating some concept to a digital form for use by the computer. For example, ASCII is an encoding scheme for English alphabet and punctuation. In ASCII, the letter "A" is encoded as the value 65, or 1000001 binary. In fact, ASCII stands for "American Standard Code for Information Interchange." Thus, letters placed into this "code" are encoded in ASCII form.

Similarly, in AutoCAD, we have to translate things like geometry and attributes into a digital code to be interpreted by the computer and stored on the hard drive. DXF is one form of encoding. DWG is another. So, the concept of a red line from 0,0 to 1,1 would be encoded as some series of binary numbers in the DWG. This is a common usage in software engineering. Unlike encryption, encoding does not imply any attempt to hide or obfuscate information.

Autodesk does respect that our customers own their own data, and we embrace and support open standards, such as DXF and DWF. In fact, we have proposed an initiative to the OpenDWG group to drive industry-wide open format, with the participation of standards groups and leading CAD software companies, to achieve a true CAD standard.

From a users' perspective, how does a developer encrypting a file format affect your future accessibility to your data? From a legal point of view, copyright in the software (including the algorithms for encryption and compression) is owned by the developer. The user of the software uses it under terms of a license. If the license to use any software terminates, the user will no longer be entitled to run the software and therefore will no longer be able to lawfully "open" the files he or she created without infringing the copyright in the software. It would be a similar case if you did not own the land in front of your house: thus by having no rights to cross the land you would not be able to get to your own front door!

Know your rights

So, does the CAD user have any "rights" in the CAD data locked in the encrypted file? The answer is "yes": he or she has copyright in the material entered, but cannot access that data without the permission (i.e. license) of the software owner. Unless the license makes specific mention of post-termination rights to access the files, (which Autodesk does not) or a court could be persuaded to imply that license, the user's data is effectively held to ransom by the software company. If the user didn't like the original license terms on offer (which no one ever reads anyway) he or she shouldn't have entered into the agreement in the first place.

So how can you increase your certainty of being able to access your data in the future?

  1. Keep a paper copy of all drawings issued
  2. Keep an electronic copy of all drawings issued in an independent file format such as PDF or HPGL

Both of the above will assist with access but neither really solves the problem, as they are only useful for accessing drawings for review or printing. They would be useless should you wish to make changes or use the drawings as a base for extension or decommission by the owner/operator.

Indeed, if you wish to access your data in an editable format, thus reducing future duplication through redrawing, you will need to start with a file format that contains editable geometry - such as DXF. However, DXF has its own problems and will only store geometric descriptions of data, i.e. lines, arcs and circles. It cannot contain the "extended" data, which is becoming more commonplace in CAD use as designers desire that their drawings "talk" to each other and "talk" to the design team.

Alternatives to DXF

So if DXF is not up to the task then what is? Well, a few people got together in 1995 to launch the International Alliance for Interoperability (IAI). Their collective aim was to specify and develop a mechanism for transporting and translating CAD data between applications without losing any of the extended information associated to the geometry.

Unfortunately for consumers the IAI has been slow to gain momentum, possibly because of its committee-like organization and possibly because some of the larger CAD developers do not want a tool that makes it easy for their customers to share information with no loss of depth or intelligence. Why? Because that may open the door for the users to look around and select another CAD application as their editing tool of choice, breaking the chains that tie them to any one system.

In a recent online debate between Philip G. Bernstein of Autodesk and Keith Bentley of Bentley System1, two quite opposing views were discussed and at some times argued. At one point, Keith Bentley stated, “Bentley explicitly disclaims ownership of file content." This was reinforced by Bentleys' announcement earlier this year to open up its new DGN file format to make DGN data accessible to any third party developers who wish to capitalize upon it. When Bentley asked Bernstein if Autodesk’s "encryption" of the 2004 file format suggested otherwise, Bernstein replied, “The fact that the AutoCAD 2004 file format is encrypted does not change the owner's right to use it." While it may not change your rights to access the data it certainly changes your ability to access it! I wonder if Bernstein’s comments were an admission of encryption or a merely a slip of the tongue under pressure? In any event the state of the 2004 DWG file remains uncertain and no independent body has proven beyond all reasonable doubt that it is encrypted, nor has Autodesk proven otherwise. [Editor's note: In a follow up to this article, Autodesk did state that Bernstein was incorrect: the files are encoded--not encrypted.]

To be able to store your data in a format with certainty of future  access, the best route forwards appears to involve covering all of your bases by implementing an improved multi-format archive procedure for all completed projects. And if you wish to retain the "extended" data together with the geometry, then perhaps the open DGN file format will prove itself to be a slightly safer bet. At the very least as a customer you may choose to vote with your checkbook and refuse to upgrade to 2004 from earlier, "open" versions of AutoCAD.

About the Authors

Joe Croser is the managing partner with CroserConsulting, a CAD consultancy in London, and a respected industry commentator writing regular features for the Architects Journal as well as contributing to AEC Magazine, upFront.eZine, TenLinks and Joe studied architecture in Oxford and has previously worked with some key industry practices including the Richard Rogers Partnership where he was instrumental in the development of CAD and IT strategy for BAA's Terminal 5 and the Millennium Dome in Greenwich.

Robert Downing is a Senior Associate in the technology group of international law firm Dorsey & Whitney MNP <> He acts for blue chip clients (including DaimlerChrysler and Nike) in relation to all aspects of intellectual property rights and has had articles published in numerous national publications. He teaches intellectual property law at Cambridge University."


1 Quotations reproduced courtesy of Jerry Laiserin editor/publisher of The LaiserinLetter" Laiserin also produced and moderated the BIM Debate. For more information visit: