Outside The Box

Debugging ObjectARX: Break on Exception

2008-05-12T12:11:00.004-04:00

I have presented a class entitled High Octane ObjectARX at Autodesk University the past two years. In 2006 the focus was on project organization, and last year I focused more on techniques for supporting multiple versions of AutoCAD with a single Visual Studio solution, touching briefly on testing and profiling. For 2007 I plan to focus on debugging.

To get you in the mood, I decided to blog about a capability of Visual Studio that often goes unnoticed and unused: breaking on an exception. This works just like breaking on a code breakpoint, except the debugger breaks execution *before* the exception handler gets control, thus allowing you to get a clearer picture of what was happening immediately before the exception occurred.

In an ObjectARX project, all kinds of exceptions can occur. Sometimes they are perfectly normal exceptions caused by and handled by AutoCAD. Many times, especially during development, your code triggers an exception that causes AutoCAD to crash, and it's not obvious what caused things to go haywire.

When unexpected things happen while running your code under the debugger, the first order of business is to inspect the debug output window to determine what happened. The debug output window (Debug->Windows->Output) displays a message whenever an exception occurs. Sometimes a series of exceptions occur, usually all caused by the same root problem. Breaking when the first exception occurs will likely yield the most useful information about the cause.

Once you examine the debug output window to determine the type of exception that occurred, open the Exceptions dialog (Debug->Exceptions) and tell Visual Studio to break when the exception is thrown:

Visual Studio contains a prepopulated list of common exceptions to choose from, or you can add new ones if you need to break on an exception that is not already listed. Many times, breaking when the exception is thrown allows you to inspect the stack trace to determine which one of your functions is to blame -- and in the vast majority of cases, it will be your code that is at fault!

Hotel Autodesk

2008-04-30T13:06:00.004-04:00

Steve Johnson asks "where have all the developers gone?", and Deelip Menezes wonders in a comment whether Autodesk's annual release cycle for AutoCAD is part of the problem. I've always said that an annual release cycle is untenable. The annual release cycle is motivated by Autodesk's desire to make the subscription program look attractive. Has it worked?

Based on what I've read and heard through the grapevine, it has definitely worked. More customers than ever are choosing the subscription model. In many cases, the annual subscription business model actually works well for software like AutoCAD, providing benefits for both Autodesk and their customers. But subscription is not for everyone.

In typical greedy big corporate fashion, Autodesk have overplayed their hand. Instead of concentrating on those customers for whom subscription makes sense and leaving the others to choose a different model, the "more is always better" marketing machine kicked in. Ergo, the annual release cycle carrot and the AutoCAD retirement program stick were invented. [Oh sorry, it's called the Autodesk Loyalty Program.]

I am already seeing the beginnings of a movement of discontent among Autodesk customers, and I expect the annual release cycle to collapse under its own weight within another year or two. In the meantime, tremendous damage is being done. Customers, third party developers, authors, and consultants all suffer under the strain of the annual release cycle, but that's only the tip of the iceberg.

To pull off annual releases, Autodesk have to be working on multiple versions of AutoCAD in parallel. While AutoCAD 2006 was being beta tested, AutoCAD 2007 and 2008 were already under development, and AutoCAD 2009 was already in the planning stages. When CUI was first introduced to the public, the new ribbon UI was likely already in the planning stages. Is it any wonder that the angry feedback about CUI was ignored?

When you have an annual release cycle with 3 or 4 future releases on parallel tracks, you can't just stop and fix a fundamental design flaw. All you can do is increase your public relations budget. The harm done to third party developers is substantial, but the inability to shift gears and correct fundamental design flaws is the real travesty of the annual release cycle.

ManuSoft Software Updated for AutoCAD 2009

2008-04-16T02:10:00.003-04:00

QuikPik and Periscope are now available for AutoCAD 2009, and SuperPurge will be available later this week. QuikPik users, note that the quick buttons feature does not work with buttons on the new ribbon UI.

The Day the ObjectARX SDK Died

2008-03-27T16:09:00.003-04:00

Like that day almost 50 years ago, could today be the day that ObjectARX has died?

There have been a flurry of posts in the ObjectARX discussion group about problems downloading the new ObjectARX 2009 SDK. At first I dismissed the problems as new release hiccups, and expected things to get resolved in short order. Seeing that there were no new complaints this morning, I headed over to http://www.objectarx.com/ to download the new ObjectARX 2009 SDK. Instead of the new ObjectARX 2009 SDK, I received the following:

Maybe it's a technical problem with the web site, and the download just didn't start, I thought. I checked my email, and found this from Autodesk:

Thank you for your interest in development tools for Autodesk's products. If you are not already an Autodesk developer partner, be sure to visit the Autodesk Developer Network website at http://www.autodesk.com/joinadn to learn more. As a member, you can access timely technical information, training and support to help you stay competitive.
If you are looking for self-help resources for your Autodesk software-based development efforts, visit our Support page at http://www.autodesk.com/support or access the ObjectARX newsgroup at news://discussion.autodesk.com/autodesk.autocad.objectarx.
Regards,
The Application Development Team

Putting two and two together, it looks to me like the ObjectARX SDK is no longer freely available. It's not altogether surprising that Autodesk would try something like this in an (almost certainly misguided) attempt to make it more difficult for organizations like the Open Design Alliance to reverse engineer the API.

If this is true, I foresee a major sea change with a ripple effect that will change the face of third party add-on development. It's a risky legal maneuver, first of all. Any time a large corporation like Autodesk picks and chooses who it will do business with, it risks running afoul of the Sherman Antitrust Act. Secondly, the practical effect of limiting access to Autodesk's SDK will be to give Open Design Alliance more influence vis à vis its DRX SDK.

For now, there is not too much of an immediate impact. AutoCAD 2009 is binary compatible with AutoCAD 2007 and AutoCAD 2008, so software developed with those SDKs will work in AutoCAD 2009 (of course without utilizing the new features). Therefore, development of AutoCAD 2009 software can continue with only a minor hit. The problem will not be felt until the next release of AutoCAD, which presumably will no longer be binary compatible.

Where is all this headed? I'm still holding out hope that it's all a big misunderstanding; otherwise we're headed for some upheaval in the AutoCAD add-on industry.

[Update: as of early Friday morning the ObjectARX 2009 SDK download is now working!]

Creative Marketing

2008-02-23T10:33:00.002-05:00

This Autodsys press release made me chuckle. Their IntelliCAD based AcceliCAD now supports custom entities, announces the press release. "Instead of creating custom objects as is necessary in some other CAD packages the application developer can instead use the primitives already built into the program such as LINEs, ARCs, CIRCLEs, and POLYLINEs." Hmmm, that sounds an awful lot like blocks in AutoCAD -- a feature AcceliCAD has surely supported since its inception.

The press release continues, "That means there is no need to define grip points or editing operations for the entities because those functions are already built into AcceliCAD."

ObjectARX programmers have been able to create custom objects in AutoCAD for years. One of the most common reasons for creating a custom object is to "define grip points or editing operations". Otherwise, blocks work just fine in most cases.

Maps Are Evil

2008-01-16T23:55:00.000-05:00

One of the defining characteristics that distinguish humans from computers is our ability to act irrationally. Our biological computer system is capable of interjecting an otherwise logical thought process with random perturbations that often result in completely unpredictable outcomes. Looked at in the abstract, this is the essence of how we escape the shackles of destiny and turn an otherwise mundane march of time into a serendipity of human experience.

In practical terms, it's our ability to make mistakes that gives us supremacy over mere electronic circuits. If we were simply pre-programmed machines, we would be no better, and perhaps no different, than a computer. By making mistakes, we learn. By taking risks, we discover. By challenging and disregarding what is already known, we learn what is not.

And that, my friends, is why maps are evil.

Periscope Speaks HTML

2007-12-22T17:06:00.000-05:00

I hit the jackpot at Radio Shack, so I'm back early from my last minute Christmas shopping today. That means I have time to tell you about the new Periscope 4.0 just released this week, in case you're looking for a last minute stocking stuffer for that CAD geek friend of yours that already has everything.

Periscope shows information about the entity beneath your AutoCAD cursor in a tooltip window ("scope window") as you hover over an entity in AutoCAD. Periscope 3 added a COM interface that made it very easy to program a custom "extender" that added to or modified the displayed entity information. Periscope 4.0 goes even farther -- it uses an excellent open source class by Eugene Pustovoyt to render simple HTML in the scope window. Custom extenders for Periscope 4.0 can now use selected HTML tags to format and beautify their output.

If you're upgrading from a previous version of Periscope and you already use a custom extender, note that you will need to make a few minor modifications to your extender code. In addition to referencing the new type library (now version 4.0), you'll need to add a new "GSMarker" argument to your extender's AddScopeText event handler.

I've added a new .NET sample extender to show how easy it is to write a Periscope extender in .NET via COM interop. AutoCAD Map 3D 2008 and Topobase 2008 users, check out the commented code in the .NET sample extender to see how you can display feature data in the scope window!

Happy Holidays!

Blog Posts Immortalized

2007-12-15T19:18:00.000-05:00

I've created a compendium of two previous series of blog posts on my web site for posterity (and easier reading):
I'll take web sites for $200, Alex
Digital Signatures in the CAD Industry

Digital Signatures: Practical Guidelines

2007-12-10T21:17:00.000-05:00

We use digital signatures every time we visit a secure web site. Visiting a secure web site involves an authentication process that includes verifying the identity of the server by ensuring that its digital certificate, or "server certificate", is signed by a trusted certificate authority. This verification process might involve verifying an entire chain of certificates from the actual server certificate up through one or more intermediate certificate authorities and ending with a trusted root certificate authority. This all takes place quickly and automatically before the web page is displayed in your web browser because the web browser includes built in logic to do this work without any user interaction. More importantly, the web browser warns us when the server certificate is expired or invalid.

The biggest obstacle when using digital certificates in a CAD environment today is not creating them, but easily and automatically verifying them at the receiving end. Even in a completely digital distribution system where everybody works from the CAD model, the various software tools we use to view and work with the model do not handle digital signature verification automatically in a standardized way. As long as downstream consumers of CAD data cannot easily and automatically ensure the trustworthiness of digital data, they will continue to rely on handwritten signatures on paper.

A second obstacle to the use of digital signatures is the difficulty in accepting that digitally signed data is only trustworthy while it remains in digital format, and therefore the digital file is the "record" document. There is substantial social inertia that must be overcome before a digital document can gain the same amount of trust as a paper document. Engineers and architects must deal with the specter of previously hidden meta data in their CAD models becoming part of their signed document, thereby exposing them to new liabilities that don't exist with paper drawings. Construction supervisors must learn to refer to the CAD model instead of relying on hardcopy blueprints when resolving disputes or establishing responsibility for errors. Here I think it should be noted that the use of a digitally signed model does not preclude the creation of hardcopy blueprints. Those can be created and "wet stamped" separately at the same time the CAD model is signed digitally; or they can be created in the field for reference without any signature at all.

AutoCAD has supported digital signatures for several years, but using the built in functionality is limited to only individual DWG files, lacks support for co-signing (more than one person signing), and forces the signed document to remain in the proprietary DWG format or lose its signature. These problems can be worked around by using third party tools, but doing so requires recipients to use the same tools.

Over the past few years, many government plan review bodies have amended laws and administrative rules to accommodate digital signatures as part of the plan review process. Without standardization, however, organizations still struggle to effect the necessary changes in their workflow. A lack of uniformity in terminology from one set of regulations to another adds to the confusion. If you are involved in amending or creating rules or regulations that enable the use of digital signatures, you should use generic and well defined terms of art in the regulations, but supplement these with practical guidelines that mention specific technologies, software tools, and file formats that will meet the legal requirements and that you are capable of working with.

If you are an architect, engineer, or CAD manager working to implement digital signatures into your firm's workflow, there are some concrete steps you can take to make the task easier. Start by segregating your distribution network into "digital-only" and "hardcopy" classes of downstream users. Begin the transition with the digital-only part of the network (perhaps only the plan reviewing authority, for example). Next, decide which file format to use for your digital "documents". Rather than signing CAD files, many companies start by signing 2D output files such as PDF, DWFx, or XPS. These files are essentially digital versions of the hardcopy documents, so they are more familiar to a wider audience and avoid some of the liability issues of exposing formerly hidden metadata that lives within the CAD model files.

You'll need to obtain a digital ID and establish internal policies for storing and accessing the digital ID so that only the owner of the digital ID ever has access to the private key. Windows includes a built in certificate manager that you can use to view and manage your digital IDs. To start the certificate manager, run the certmgr.msc management console by entering its name in the Start -> Run command window. Your digital certificate will be installed in your personal certificates folder along with a link to the private key stored in the Windows secure key repository. Make a backup of the digital ID by exporting it to a password protected PFX file. Once a backup is made, the private key should be marked as not exportable to further secure it.

If you want to create digitally signed AutoCAD DWG files, you can use the digital signature feature of AutoCAD to sign a drawing file either while saving it or after it is saved. You should also consider subscribing to a commercial time service (see What time is it?) to ensure that your signatures are accompanied by a reliable time stamp in case your digital ID becomes compromised at some point in the future. Third party tools like CADVault for AutoCAD even make it possible for different people to sign different parts of the CAD model, but such advanced functionality is not needed in most cases.

If you use different CAD software that does not support digital signatures natively, or if you choose to sign only the secondary files produced by exporting your CAD model to a different format, then you will need to use either tools specific to that format or third party tools that work with files of any format. Adobe Acrobat (PDF) and Microsoft's free XPS Viewer both provide integrated digital signature tools that use the same digital IDs that you would use in AutoCAD, Internet Explorer, or Outlook/Windows Mail, and both applications are easy for recipients to obtain and use.

Another popular tool for managing digital IDs and signing files is an open source tool called GnuPG. GnuPG utilizes encryption and key storage standards called OpenPGP. OpenPGP is not compatible with the X.509 standard used by Windows and many other encryption tools, however it is an attractive alternative when cost or closed source tools are a prohibitive barrier. There are many other digital signature resources available on the internet for those wanting more information, or needing specialized tools.

Unfortunately, no matter what software tools or file formats you use, today's CAD software and document viewers still do not provide the user experience that web browsers do when it comes to digital signatures. These problems can be overcome by end users, but ultimately they need to be addressed by the makers of the software tools we use. Software for handling digital data will need better user interfaces that allow users to easily specify which digital signatures should be trusted for which purposes, and provide requisite warnings when a document should not be trusted. I am confident that these improvements will come in the future, especially as more companies begin to use digital signatures in their workflow and demand for better digital signature support rises.

If you already use digital signatures with your CAD related documents, I would like to hear about it. Please leave a comment about your experiences, whether good or bad!

Digital Signatures: Under the Hood

2007-12-10T21:15:00.000-05:00

The basic requirements of a digital signature are that it must uniquely identify the signatory, it must be independently verifiable, and it must be invalidated if the signed data has changed. To understand how these objectives are achieved, let's start with the foundation of modern digital signature technology: public key encryption and the public key infrastructure, or PKI.

In public key encryption, a "key pair" consists of two parts: a public key and a private key. In simplistic terms, the public key is mathematically derived from the randomly generated private key using an algorithm known as a "one way function". A one way function makes it easy to calculate a public key if the private key is known, but extremely difficult to deduce the private key if the public key is known. The end result is a secret private key and an openly shared public key that are mathematically related in such a way that the public key can be used to decrypt data that was encrypted with the private key, and the private key can be used to decrypt data that was encrypted with the public key.

This interesting property of such a key pair gives rise to a number of useful capabilities. In the case of digital signatures, the act of signing data is essentially nothing more complicated than encrypting the data with a private key. If the data can be decrypted successfully with the signer's public key, then only the signer's private key could have been used to do the encrypting. In practice, this process is simplified so that the signer encrypts only a secure hash, or checksum, of the data to be signed. The recipient then calculates the hash from the raw data and compares the result with the "signed" hash after it is decrypted. If the values match, the digital signature and data are validated.

For this process to work properly, there need to be standard ways to package information about the algorithms used, and to provide important information about the keys themselves. This need is fulfilled by digital certificates. A digital certificate is a file or block of memory containing a public key along with ancillary data about the key and its owner. The certificate is itself digitally signed by the entity, usually a mutually trusted third party, that issued the certificate. This enables users to verify that the public key is valid and trustworthy.

A digital ID is the private key component of a key pair. Normally the private key is not stored together with the public key, but instead is stored in a separate physical location for security, usually requiring a password to access it. A key manager maintains links between the digital certificate and its associated private key. In many cases, it is convenient to use the term "digital ID" to mean both the public and private keys, even though they are physically separated.

It is almost always a good idea to time stamp digital signatures. Time stamping involves sending the digital signature to a time stamp authority, who then creates and returns a digitally signed time stamp that is uniquely and securely associated with the original digital signature. The time stamp can then be verified by third parties in the future by using exactly the same technique used to verify a digital signature.

I think these important terms deserve a review. A "digital certificate" is a public key, which is itself digitally signed by a mutually trusted third party. Your digital certificate represents your public digital identity, and it should be made freely available to anyone who wants or needs it. A "digital ID" is a digital certificate and the private key associated with the digital certificate. It isn't difficult to create your own self-signed digital ID, but a digital ID is only as good as the issuing authority that signs it. When you purchase a digital ID from a third party like VeriSign or Thawte, their reputation makes your digital ID more trustworthy.

Digital Signatures: Philosophically Speaking

2007-12-10T21:11:00.000-05:00

There is nothing magical about digital signatures. They are simply an electronic mark used to signify a promise and to cement faith in the document or transaction to which that promise is attached. Some day digital signatures will be as commonplace among CAD professionals as the human readable "wet stamp" is today. However it must also be said that, just as CAD did not make architects more creative, digital signature technology will not make engineers more trustworthy.

The technology to use digital signatures has been around for well over 20 years, and a wide variety of software tools exist today that make digital signatures easy to use on almost any platform. So why is the use of digital signatures not more widespread? Primarily because the utopian dream of a paperless world has yet to materialize.

So long as hardcopy on paper is regarded as the authentic "record" version of a document, digital signatures are virtually useless. Even if new buildings are designed completely in CAD, an architect's digital signature simply won't mean anything if downstream consumers of the building design require a paper blueprint. The true benefits of a paperless world simply can't be realized until every link in the chain has joined the digital club. So long as even a single node on the distribution tree requires a human readable method of verifying authenticity, the architect is forced to use a handwritten wet signature on paper blueprints from the very start.

Handwritten signatures can be scanned into an electronic format, but then they lose their putative value because a digital facsimile is so easily reproduced. Therefore only original and unique handwritten wet signatures are trustworthy in a human readable form. Digital signatures do not translate to paper because they are not human readable. Therefore digital signatures only have value for a document in electronic form. This maxim is fundamental to a proper understanding of the emerging digital signature technology: digital data can only be securely signed by computers; and human readable documents can only be securely signed by humans.

I see many people in the CAD industry looking for a hybrid solution to this paper vs. digital dilemma by using a "digitized signature" (i.e. handwritten on paper, then scanned into electronic format) so that printed output contains this digitized signature. This cannot even remotely be considered a digital signature! There is simply no such thing as a secure printed digitized signature. Yes, you can digitally sign a document that has an embedded digitized signature, but once it is printed, that digitized signature is not worth the paper it's printed on. Not only could that signature be stolen from the document and used maliciously, there is no way to tell from the signature alone whether or not it has already been stolen and used maliciously.

The only hybrid approach that is practical and legally sound is to use digital and wet signatures in parallel. Using an architect as an example, this would mean creating and disseminating two sets of signed documents: the CAD model of a building (perhaps converted into a common 2D format like PDF, DWFx, or XPS) with the architect's digital signature and paper blueprints with the architect's individually handwritten wet signature.

A number of companies claim to sell some sort of hybrid solution involving the creation of a secure digitized signature. This is simply capitalism -- selling something useless just because there is a market for it. A digitized signature is only secure if it is never used. I've heard the rationalization that the digitized signature printed on paper meets a psychological need for people accustomed to seeing one, even if it has no legal value. In my opinion, such pandering borders on deception and serves only to further alienate digital signature technology from those who would benefit from it. This sort of abuse is typified by an emailed PDF file consisting of a scanned document with a handwritten signature. In such cases, checking the sender's email address likely becomes the most reliable way to verify the document's trustworthiness. Spam filters bear witness to the fact that the sender's email address is the most important -- and often only -- criteria we use in determining the level of trust to place in emailed documents. This is an important point to keep in mind.

The act of applying a digital signature requires the use of a secure private encryption key, but the digital signature alone does not provide security in any way. Digitally signing a document does not prevent it from being modified or stolen. In that respect it is no different than a handwritten wet signature. However, unlike a wet signature that cannot be easily duplicated, a digital signature does not prevent a signed document from being copied. This does not make digital signatures inferior. On the contrary, making copies is necessary and commonplace in the digital world, so the fact that exact copies of digitally signed documents are still trustworthy is a huge benefit over handwritten signatures.

There are other notable differences between a digital signature and a handwritten signature. Digital signatures can be time-stamped, thus providing reliable evidence that a document was signed on or before a certain time. A disadvantage of digital signatures is that they are only as reliable as the digital ID used to create them. To combat this problem, a public clearinghouse of compromised digital IDs must be maintained, and auditing systems must be in place to immediately detect and report suspicious activity. Time stamped digital signatures created before a digital ID is compromised can be easily and certainly distinguished from compromised signatures if properly designed and competently managed infrastructure is in place. This is necessary to ensure that previously existing digital signatures survive a compromising event.

In conclusion, adequate technical solutions and time tested safeguards already exist for successfully using digital signatures in a professional environment, but digital consumers still need to learn how to work within the limitations of the technology. Building an acceptable comfort level with a technology that must by its nature completely replace something as significant and culturally ingrained as the handwritten signature will not be easy or quick, but it is inevitable.

Digital Signatures: Prelude

2007-12-10T21:07:00.000-05:00

For many, the word "encryption" has a mysterious quality that invokes images of math virtuosos in secret bunkers working feverishly during wartime to break the enemy's coded communications. My first exposure to encryption came in 1996 when I began working with Paul Kohut on the first version of CADLock software for locking AutoCAD drawing files. After overcoming my initial struggle to understand the terminology and get a handle on the mathematics behind encryption, I realized that it wasn't nearly as mysterious and complicated as it first appeared.

I knew it would take a long time for encryption terminology to become standardized and commonly understood by laypersons. From the first days of CADLock, we recognized that the key to success for our software was going to be our ability to educate consumers about our technology, it's possibilities and its limitations, its strengths and its weaknesses, what it could do and what it could not do. I felt that we needed to be realistic and patient while we waited for the market to catch up with our technology at its own pace. In the meantime, we needed to resist any temptation to needlessly bandy about sexy buzzwords like "encryption" lest we delay our mission by further muddying the waters in an already crowded ocean of technical jargon.

This recognition of the need for patience and perseverance has led me on a personal crusade to prevent encryption terminology from being perverted or hijacked by overeager marketing departments and uninformed experts. I've also tried to nudge the learning process along by adding my two cents whenever the opportunity arises. With this last goal in mind, I have prepared the following three part essay about digital signatures, tailored for the CAD industry. This is not written to academic standards, nor do I claim to be the final authority on the subject. Let me be clear about my agenda: I hope that furthering the common understanding of encryption related technology such as digital signatures will indirectly help sell more CADLock software!

AU 2007 Post Mortem

2007-12-03T15:12:00.000-05:00

The Hot List

Carl Bass munching on fast food in the food court, and spotted throughout the week yakking with average folks in the halls.
Staggered classes reduced the lunchtime crush experienced at AU 2006.
More ObjectARX programming classes this year. I'm pushing for creating a new "Developer" track for AU 2008.
The Matt Murphy Head (peace be upon him).
Meeting a lot of familiar faces and a few new ones!

The Cold List

The food was worse this year than even AU '97 in Los Angeles. At least AU '97 had a Burger King nearby for someone on a budget; here in Las Vegas I ended up spending several hundred dollars over the course of the week just for food.
Pete Kelsey's band, Dr. Ruth, didn't play. Rumor has it that the AU organizers refused to give them space. Dr. Ruth has become an AU staple, and it just wasn't the same without them.
Shaan Hurley's gut-wrenching regimen for clearing 20 year old meat byproducts from various body cavities.

I presented the first of two ObjectARX roundtable discussions this year (the second one, hosted by Stephen Preston, also covered .NET). This was an experimental format. I liked it, and I thought it went well. If you were there, I'd like to hear your suggestions for making it better next year. I will be following up with some more posts covering topics raised in this and other AU classes.

VC Build Hook utility for Visual Studio 2008

2007-11-26T02:27:00.000-05:00

The new Visual Studio 2008 has been released, and to celebrate, I've updated VC Build Hook. The updated utility allows you to use the new IDE while still building with older versions of the build tools.

Why is this necessary? If you build your AutoCAD 2007/2008 ObjectARX application with the Visual C/C++ 9.0 tools, AutoCAD will display a warning message about an incompatible module when you try to load it. You can use VC Build Hook to target all previous AutoCAD versions from a single Visual Studio 2008 solution (if you have the correct version of Visual C/C++ installed alongside Visual Studio 2008).

In my testing so far, existing Visual Studio 2005 projects build without problems in Visual Studio 2008 when VC Build Hook is installed and the new 'BuildToolVersion' property is set to the correct version.

OpenDCL 4.1 Released

2007-11-21T10:50:00.000-05:00

OpenDCL 4.1 adds support for the AutoCAD 2008 64-bit platform, includes many improvements in the OpenDCL Studio editor, and has a completely rewritten grid control.

Next on the agenda is adding support for localization so that local language translations can be easily created.

The War On Security

2007-11-01T14:35:00.000-04:00

Security and encryption legend Bruce Schneier posted this essay:
The War on the Unexpected

I think we should all be reminded that representative governments are always at risk of death by democracy: suicide under the watchful eyes of a body politic beholden only to the next election.

Autodesk Resale Prohibition Under Attack

2007-09-11T05:40:00.000-04:00

I've just posted at ADSKvODA.com about a new lawsuit filed by Timothy S. Vernor of Seattle accusing Autodesk of using fraudulent means to enforce its license agreement prohibition on reselling legitimately purchased software. This subject comes up often, and I think there is a lot of grass roots support for Mr. Vernor's argument extending well beyond Autodesk customers.

The license agreement is not the central tenet of the lawsuit, but questions about its legitimacy do come into play. The legal principle involved is called the First Sale Doctrine, which essentially exempts buyers of copyrighted works from copyright infringement claims when they resell the work. The nebulous legal framework around so-called "shrink-wrap" software licenses, and the degree to which the First Sale Doctrine applies to software, is still an open question here in the US.

For those of you interested in learning more about the First Sale Doctrine, listen to this podcast discussion on the Technology Liberation Front web site.

AutoCAD 2008 Slow Startup Fix

2007-09-06T16:54:00.000-04:00

I've noticed more frequent posts in the Autodesk discussion groups about slow startup problems since AutoCAD 2008 was released, and I have the same problem on my development system. Part of the problem is .NET loading, due to the new .NET gadgets like the dashboard palette. Another long running startup hassle is the communication center (WSCommCntr1.exe if you check running processes in task manager) that Autodesk products use to call home.

In addition to the time the communication center process takes to start up, it can also get "stuck" (either due to network or connection problems, or because of AutoCAD crashing) and cause interminable startup delays. If AutoCAD is trying to start while the communication center is "stuck", it will wait in a completely frozen state for about 2 minutes before it times out and loading continues.

In addition, AutoCAD 2008 service pack 1 introduced a new "pure virtual function call" C runtime error that shows up when the communication center closes after an AutoCAD crash.

All these problems can be easily fixed by disabling the AutoCAD InfoCenter, which is the culprit that loads the communication center background process. I disabled it by changing the demand load registry key for the InfoCenter. That key can be found in the registry at:

HKLM\Software\Autodesk\R17.1\[ACAD-XXXX:XXX]\Applications\InfoCenterAcConn

Change the LOADCTRLS value to 0 (zero) to disable it from demand loading.

If you disable your InfoCenter from demand loading, you can still load it manually by using the NETLOAD command to load AcInfoCenterConn.dll from the AutoCAD 2008 folder.

Brutal

2007-08-17T22:45:00.000-04:00

I've heard the word "brutal" used more than once during conversations with Autodesk employees about the Autodesk sponsored discussion groups. It's true that raw unfiltered feedback can be brutal, and it can also hurt your ego if you happen to be the target of criticism. The trick is to learn how to interpret the feedback. If you can master that skill, that raw feedback is a fast, unbiased, low noise-to-signal-ratio predictor of the future.

I've seen many recognizable Autodesk names come and go since the days of Autodesk's original online discussion group, the CompuServe ACAD forum. Oftentimes, they came espousing the virtues of such a vibrant community, only to wilt away after they got singed a few times in the inevitable flame wars. Some Autodesk names (Art Cooney comes to mind) have been around forever, and still take it all in stride. Personally, I view the discussion groups as one of Autodesk's biggest competitive advantages, even while they go largely untapped.

This week saw too issues erupt into what could fairly be termed brutal feedback. The first was caused by the Autodesk University registration site failing under the load of opening day registration. Several threads ("Dear Carl Bass" and "AU2007 Registration is now open!!!") called Autodesk to the carpet for blowing it again, after a similar fiasco in 2006.

The second event occurred when AutoCAD product manager Eric Stover announced a new "bonus" tool called CommandComplete. I pity the poor guy or gal that wrote this tool (on their own time, I'm sure), all excited to see how it is received, only to become the victim of a flame war. Okay, not really a flame war in this case because Eric employed his finely tuned flame retardant diplomacy skills to prevent it from getting out of hand -- so let's just call it a "venomous reaction".

There is a moral to this story. Some companies would kill to have access to this kind of critical, unfiltered, instantaneous feedback from the unwashed masses. I hope Autodesk recognizes the goose that lays the golden egg.

OpenDCL 4.0 Debuts

2007-08-01T10:51:00.000-04:00

OpenDCL 4.0 has finally been released. If you're not familiar with OpenDCL, check it out at www.opendcl.com, or on SourceForge at sourceforge.net/projects/opendcl.

OpenDCL, based on the original commercial ObjectDCL software by Chad Wanless, is a modern replacement for the old DCL dialog control language in AutoCAD. The current OpenDCL Runtime supports AutoCAD 2002 through 2008 (except AutoCAD 2008 x64). It is designed to give AutoCAD end users and AutoLISP application developers a simple yet powerful way to design and use rich user interfaces in their applications.

The goal for version 4.0 was to get it stable and fix all the bugs, with minimal new feature development. OpenDCL 4.1 will add support for AutoCAD 2008 x64. After that we will start working on localized language versions, and adding new features.

OpenDCL is licensed under the GNU General Public License (GNU GPL) open source license, completely free to use, and source code is available on SourceForge.

What time is it?

2007-06-21T21:13:00.000-04:00

AutoCAD 2004 introduced the ability to digitally sign drawing files when they are saved, but very few people use this feature. Even fewer use the time stamp feature that goes along with it. Time stamping a digital signature is important when it's not only important to know *who* signed it, but also *when* they signed it.

For time stamping to be reliable and trustworthy, you need an independent (and trustworthy) third party to provide the time stamp, along with a verifiable receipt so that anyone can verify the authenticity of a claimed time stamp in the event of a future dispute.

Since the inception of the digital signature feature, AutoCAD has included three default time servers for this purpose. Unfortunately, none of the three are accessible any more. If you need to digitally sign drawing files with a time stamp, you'll have to modify this list of time servers.

The list of time servers is maintained in a file named timesrvr.txt in the AutoCAD installation folder. You can edit the file with notepad, and the format is obvious and straightforward when you view the file.

If you just want to play around with time stamps, try adding the following to the end of the file (you do not need to restart AutoCAD to see the new servers):
NIST A [Maryland] (time-a.nist.gov)
NIST B [Maryland] (time-b.nist.gov)

As of this writing, both of these NIST servers are available and working, but you get what you pay for. For officially incorporating time stamped digital signatures into your workflow, I recommend subscribing to a commercial time service with guaranteed uptime and a web based time stamp verification console. I can't recommend one, because I have never used a commercial time service myself, but a good place to start is the list of public time servers maintained by NTP.org at http://support.ntp.org/bin/view/Servers/.

Visual Studio Build Configuration Tip

2007-06-15T13:30:00.000-04:00

I've received several emails recently from users of my VC Build Hook utility that mention switching the 'UseVC7Paths' setting on and off depending on the build configuration they are working on. If you are doing this, you need to change your project structure!

Build configurations in Visual Studio 6 and later are logically attached to the solution, not to an individual project as they were in older Visual Studio versions. What happens is that programmers find it easy to add a new build configuration to an existing ObjectARX wizard created project for targeting a new release of AutoCAD -- unfortunately those configurations end up belonging to the entire solution instead of just one project. Since VC Build Hook cannot be set on a per-configuration basis, they end up having to change the project setting depending on which configuration they are building. That's bad, very bad!

The correct way to handle this situation is to create new projects, not new build configurations. Yes, it's a bit more work, and it would be nice if Microsoft added an easy way to clone a project, but them's the breaks. Targeting different AutoCAD releases requires project-level changes, so you must create a new project instead of trying to get by with a new build configuration. You can and should share source code files between the projects, however.

When I create a new multi-target solution that e.g. targets AutoCAD 2000 - AutoCAD 2008, I structure the project files on my hard drive like this:

Solution (.sln file)
\ARXProject (ARX module source files)
+ARXProject.15 (.vcproj file)
+ARXProject.16 (.vcproj file)
+ARXProject.17 (.vcproj file)
\DBXProject (DBX module source files)
+DBXProject.15 (.vcproj file)
+DBXProject.16 (.vcproj file)
+DBXProject.17 (.vcproj file)

When starting a new project, I first use the wizard to create a default project structure and source code files for the current AutoCAD release. Once I've got that set up the way I want (including moving the project file into a subdirectory and modifying the source file paths appropriately, as well as setting the _ACADTARGET preprocessor macro), I clone projects by copying the .vcproj files and editing the copies in a text editor to give them a new GUID, then recreate my solution's project structure from scratch by dragging and dropping the project files back into the solution and editing them as necessary.

If you need to target multiple AutoCAD releases from a single project, invest the time to set your solution up this way (and follow the other advice on my ARX tips page!), otherwise you will find yourself constantly fighting the system.

QuikPik, Periscope, SuperPurge Updated for AutoCAD 2008

2007-05-04T02:59:00.000-04:00

If you use of any of these ManuSoft products, preliminary AutoCAD 2008 support has been available for several weeks at the Download Center for registered users. The QuikPik and Periscope updates are now officially released, and the shareware versions of QuikPik and Periscope are now available as well. SuperPurge will be officially released in the next week or so.

My free AcadStatusBarButton library has also been updated for AutoCAD 2008, and is now available for download on the Freebies page. The only change is the addition of a blank status bar pane beneath your floating buttons so that the new annotation scale buttons in AutoCAD 2008 don't get covered up (the blank panes force the annotation scale buttons to the left of your custom buttons). If your button position is fixed (i.e. not floating), the blank pane will not be used.

As always, if you encounter any problems, please let me know!

Rational Ignorance

2007-04-22T19:11:00.000-04:00

Reading the discussion about the reluctance to move to 3D/BIM in the latest issue of upFront.eZine reminded me of the principle of rational ignorance. The principle of rational ignorance applies when the perceived cost of obtaining knowledge is greater than the perceived benefit. It's a bit of a chicken-and-egg scenario, where individuals rationalize their decision to remain ignorant based on their perception of the (lack of) benefit in the very thing they are ignorant about.

It is interesting to think about the 2D to 3D paradigm shift in terms of shifting the balance in the rational ignorance equation. I think there's also another principle at work here: Newton's Third Law. The harder the collective movers and shakers try to push, the harder the end users resist. Maybe if the software companies stopped pushing so hard, the shift would occur naturally with much less resistance.

By the way, I noticed a familiar theme in the upFront eZine discussion: those resistant to the paradigm shift lament the lost art of drafting and fail to believe that the new paradigm no longer needs artisans. Obviously there are other factors at work here -- factors over which no amount of logic will prevail.

Egyptian Pyramid Scheme

2007-03-31T10:41:00.000-04:00

Deelip Menezes asks what got me started on lamenting the sad state of the CAD industry in my previous post. Good question.

It all started with a Fox News story about a French architect's claim to have solved the "Pyramid Secret": http://www.foxnews.com/story/0,2933,262981,00.html. The article links to Dassault Systemes' web site: http://khufu.3ds.com/introduction/. My snake oil alarm went off when I saw the site. I'll admit I didn't read it, but it looks like a slick marketing ploy. I was irritated that I fell for it. It reminded me of how insideous and incestuous this industry has become, now reaching out to mainstream media in search of new victims.