Evan on Engineering Software

Autodesk's new license agreements, introduced with the 2007 generation of products, continue to show a troubling trend towards restricting compatibility and interoperability.

Here's one I just heard about yesterday: the new ObjectARX SDK license restricts its use with AutoCAD LT, DWG TrueConvert, and DWG TrueView:

You may make unlimited copies of the Software and give copies to other persons or entities so long as (i) all such copies are used to develop applications for Autodesk products based on the AutoCAD platform excluding AutoCAD LT®, DWG TrueConvert™, and DWG TrueView™ and (ii) all such copies contain this Agreement and the same copyright and other proprietary notices that appear on or in the Software. As set forth above, You may not use the Software to develop applications for AutoCAD LT®, DWG TrueConvert™, and DWG TrueView™ as the aforementioned products are non-extensible applications and the use of the Software to develop applications for these products is expressly prohibited by this Agreement.

This is rather interesting, as none of the products mentioned actually include support for ObjectARX applications – so how could a person actually use the ObjectARX SDK to create applications for them?

Technically speaking, it's not possible to write an application for a program that doesn't have the API (application programming interface) to work with it. Yet, a number of people have written programs (call them "LT API programs", for lack of a better term) that have just such an API, and work with AutoCAD LT.

If you look at AutoCAD LT as a programmer would, you'd find that it actually does have the hooks to support the ObjectARX API. This is because it's a Windows compatible program, and for it to work properly with Windows, those hooks have to be there. My understanding is that, when AutoCAD LT first came out, all of the necessary pieces to support the AutoLisp and ARX APIs were there -- but were disabled. A few smart programmers figured out how to enable them.

I have to assume that Autodesk isn't thrilled with what these programmers are doing, yet it hasn't added anything to its AutoCAD LT EULA to prevent the practice. Apparently, just because Autodesk doesn't like how someone uses their products, doesn't mean they can prevent that use. (It would be rather like Microsoft saying that you couldn't use Adobe Acrobat with Word.)

What Autodesk has done is to implement technical steps to make the process of creating LT API programs more difficult. For example, each succeeding version of LT has had more and more pieces removed -- making it so that the LT API programmers have to recreate those pieces, by writing their own versions.

I've been told by some LT API developers that one subtle trick that Autodesk uses is to build "time bombs" into LT, so that the LT APIs will work for a little while, but will break after some period of time. One of these time bombs is apparently a remapping function that periodically scrambles the memory used by AutoCAD LT. It's a rather neat trick -- except that it is a dangerous practice, and raises hell with antivirus programs.

(I went to look in Autodesk's AutoCAD LT discussion groups, to find some messages to validate this, assuming no one would believe me otherwise. It didn't take much looking. There are plenty of people complaining of suspicious LT crashes that seem to be related to time-bombs -- yet, I doubt that Autodesk will come clean, and admit the truth.)

Beyond technical measures, Autodesk has, to my understanding, started to threaten resellers and users of LT API programs, implying that the use of such programs is somehow "illegal." So far, I've not seen any smoking gun to prove this -- but I've heard plenty of stories of resellers and users who've been seriously spooked. There is little the LT API developers can do about this. Though they could sue Autodesk for tortious interference in their business relationships, the lack of a smoking gun (and a few million dollars to pay for attorneys) would make it tough to win.

The change in the ObjectARX license is the most recent and overt stone thrown by Autodesk to try and shut down the LT API developers. But what's interesting about this change is that it seems to be all FUD, and no teeth.

Looking inside the ObjectARX SDK, you can find a copyright notice that says the following: "Permission to use, copy, modify, and distribute this software in object code form for any purpose and without fee is hereby granted, provided that the above copyright notice appears in all copies and that both that copyright notice and the limited warranty and restricted rights notice below appear in all supporting documentation."

The License agreement says you can't use ObjectARX to write an application for AutoCAD LT, but the copyright notice says you can use any application you do write for any purpose.

Taking the license and copyright notice together, it seems that as long as you write an ObjectARX application for plain old AutoCAD (that is, it'll run with plain old AutoCAD), you can then use it however you wish -- even with an LT API program and AutoCAD LT.

(Some might argue that I'm relying upon a very subtle reading of the ObjectARX license agreement. I think it's worthwhile to mention that Autodesk employs a number of very highly compensated attorneys to draft their agreements. Each word that is or isn't in the agreements is almost certainly intentional. If Autodesk had meant that you could only use the ObjectARX SDK to develop applications that would only work with the versions of AutoCAD that they specified, the agreement would have said this. Given Autodesk's history, I assume that the reason they didn't was that it would have created legal or regulatory problems for them.)

The issue here is not that the LT API developers are doing anything wrong -- it's that Autodesk doesn't want the APIs in AutoCAD LT enabled, because doing so cuts into the sales of their more expensive products.

A better solution for Autodesk, rather than adding time bombs that make AutoCAD LT crash, and threatening resellers and users, might be to consider offering people what they want: reasonably priced CAD software that can be customized.

Important note: I'm not a lawyer, and I'm not providing legal advice. Everything I've written here is my opinion, based upon my experience, what people have told me, and what I've read. If you want legal advice, hire a lawyer.