Outside The Box

There are a myriad of ways to load AutoLISP applications in AutoCAD, including acaddoc.lsp, an .mnl file, the Startup Suite, and manually by various means. For application developers wishing to deploy their applications to others, all of these methods have drawbacks. The ideal solution should be easy to implement in an installation program, require minimal or zero changes to the user’s AutoCAD configuration, work the same way across all versions of AutoCAD, and easily undone when the application is uninstalled.

ObjectARX application developers have long used registry demand loading to load their applications automatically, either when AutoCAD starts or when the user enters a command that the application defines. Registry demand loading is relatively easy to set up and meets the other requirements for an ideal solution, except for one problem: it works only with ObjectARX modules (or with .NET modules in AutoCAD 2006 and later).

Many years ago, I created a solution to this problem by building a small stub ObjectARX module that did nothing but load an associated LISP file. This effectively allows the registry demand loading mechanism to be used for loading a LISP file. If you develop AutoLISP applications that could benefit from registry demand loading, then I have a Christmas present for you: LspLoad.zip contains a complete suite of newly updated stub modules for all versions of AutoCAD from AutoCAD 2000 to AutoCAD 2010, plus modules for Bricscad 9 and 10, which also supports registry demand loading.

To use the stub modules, just rename them so that the base filename matches your application’s main LISP filename, then install them in the same folder as the LISP file and create the registry demand load entries. The only work you have to do is to get the stub module to load. You can simply drag and drop the appropriate stub module into a running instance of AutoCAD in order to test it.

Creating the demand loading registry keys is not difficult, but it may require some programming. I write custom actions for my installation programs that enumerate all installed AutoCAD versions and flavors, and set up the demand load keys for every one. However you do it, the final result should look something like this (for AutoCAD 2010 on my system):

In this screen shot, I created an application called “!LspLoadTest” (the “!” was added just so it displayed at the beginning of the list). I added the minimum required subkeys. The LOADER string value is set to the complete path of the stub module, and LOADCTRLS is set to a value of 2, which means I want the application loaded when AutoCAD starts. LOADCTRLS is a bit coded value; for use with LspLoad, it’s only useful values are 2 or 4. A value of 4 means “load when my command is invoked”; this mode requires a COMMANDS subkey that lists the defined commands.

The way it works is very simple. In the example above, you can see that I renamed the module (but left the “.18.x64.arx” so that I can tell it apart). I then added !LspLoadTest.lsp to the W:\LspLoad folder. That file contained the following:

(princ “\nThis test file loaded from “)
(princ (if GetPathOf!LspLoadTest (GetPathOf!LspLoadTest) “<unknown>”))
(princ)

Now when I start AutoCAD 2010, I see on the command line:

This test file loaded from W:\LspLoad\

These files are free to use for any purpose. Have a great holiday, everyone!

If you’re an AutoLISP programmer, you’ve probably heard about OpenDCL. Maybe you’ve even checked it out, but it looked complicated and you weren’t sure whether it was worth the trouble to learn how to use it. Either way, do yourself a favor and spend 10 minutes to go through the following 10-step quick introduction to OpenDCL.

1. Download and install OpenDCL Studio. Select the latest version in your desired language (ENU in the filename means US English). The download is an .msi file that can be cleanly uninstalled afterward.
2. Start AutoCAD (2004 or later). Use the APPLOAD command to load _MasterDemo.lsp from the OpenDCL Studio samples folder (it will be located in a language subfolder of the main OpenDCL Studio folder). When you close the APPLOAD dialog, the OpenDCL ‘MasterDemo’ dockable form will appear.
3. Click on the [ListView] button to run the ListView sample. The ListView sample is very simple and will demonstrate some basic principles of OpenDCL. Leave it running as you proceed through the following steps.
4. Locate and open ListView.lsp in the OpenDCL Studio samples folder. ListView.lsp contains all the code for the ListView sample. Look for the c:ListViewDlg_Close_Clicked function defined near the end of that file. That function is called an “event handler”, and it is the lisp function that is executed when the [Close] button is pressed. The event handler for the [Close] button simply closes the dialog. The c:ListViewDlg_OnInitialize event handler function initializes the controls on the dialog before it is displayed.
5. Locate and open ListView.odcl in the OpenDCL Studio samples folder. Files with an .odcl extension can be opened and edited in OpenDCL Studio. OpenDCL Studio is used to design the user interface elements in an OpenDCL project. In the project tree pane, open the ‘Modal Forms’ folder, then double click on ListViewDlg. The ListView form will be displayed in design mode.
6. Click on the [Close] button on the ListView form. In the font toolbar at the top of the editor, press the [B] button to make the font bold. Notice that the button’s caption becomes bold. In the ‘Properties’ pane, double click on the ‘Height’ property value and change it to 20. Press [Enter] to apply the new value. Use your mouse to drag the bottom of the button in design view to resize it dynamically.
7. Leaving OpenDCL Studio open, switch back to AutoCAD. Resize the ListView dialog, and notice how the controls it contains are also resized. Now switch back to OpenDCL Studio, make sure the [Close] button is selected, then click in the right column of the ‘(Wizard)’ property in the Properties pane (or right click on the button control and select ‘Properties’ in the control’s context menu). In the Control Properties Wizard, the Geometry tab shows that the button’s “Left Side Alignment” has been set to “Offset From Center of Dialog” and it’s “Top Side Alignment” has been set to “Offset From Bottom Edge”. Once these properties are set, no additional code is needed for the control to react correctly when the dialog is resized.
8. Exit AutoCAD, then restart. Enter the OPENDCL command. This command demand-loads the OpenDCL Runtime using AutoCAD demand loading mechanism. The OpenDCL Runtime must be loaded before the OpenDCL functions will work. The OpenDCL Studio installation includes OpenDCL Runtime, so it already exists on your computer.
9. If you are developing an application for use by others, you’ll need to download and distribute the OpenDCL Runtime along with your application. This is best done by incorporating the OpenDCL Runtime merge module for your language directly into your own application’s installation script. Alternatively, you can distribute the standalone OpenDCL Runtime .msi file for your language, or publish the URL where end users can download the latest version.
10. Switch back to OpenDCL Studio and double click on the [Close] button control. Intelligent help displays all the properties, methods, and events of the selected control, including their AutoLISP syntax. Click on a property, method, or event in the left pane to see detailed information for it.

Once you complete these ten steps, you are only a few minutes away from creating a fully functional OpenDCL application. Give it a try!

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.

AutoLISP programmers may remember a product named ObjectDCL, by 3rd Day Software. ObjectDCL was released as open source in the summer of 2006 by developer Chad Wanless due to his inability to continue supporting the software because of “health reasons”. At the time, many users of ObjectDCL hoped that someone would update the code to work in AutoCAD 2007. Programmer David Robison did some work to get AutoCAD 2007 supported, but the project has been languishing, almost to the point of extinction.

After being asked by several ObjectDCL users whether I could help, I decided a few weeks ago to contribute to the community by getting the original C++ code updated to support AutoCAD 2007. As I am wont to do, I’ve ended up re-architecting much of the code in the process.

The results of my work are available now at the new OpenDCL project on SourceForge. The new 4.0 release is still in the alpha testing phase. If you program in AutoLISP and want to create rich user interfaces for your applications, check it out!

Some years ago I wrote a small ObjectARX module named VLXLoad that loads a .vlx file of the same name and in the same directory as the .arx module. I never claimed credit for the utility, but now that I’ve released the source code, I guess I’ll have to own up to it.

If you’re interested in seeing an example of “dynamically” defining an ADS (lisp callable) function when an ObjectARX module loads, take a look at the VLXLoad source code. The code also demonstrates how to call the GetModuleFileName() WinAPI function to get the path of the executing module, and how to declare and use the undocumented ads_queueexpr() function.

There is no documentation (and probably no comments), so be warned. The download contains ready to build projects for Visual Studio 2002 (targeting AutoCAD 2004-2006) and Visual Studio 2005 (targeting AutoCAD 2007). These projects were both created with the corresponding ObjectARX wizard, and are included in the course materials for my “High-Octane ObjectARX” class at AU 2006 as an example of a simple (yet very useful) ObjectARX application.

If you just want to use VLXLoad, I’ve also made the original pre-built binaries available on my Freebies page. The idea is to rename the correct .arx file so it matches the name of your .vlx, then set up registry demand loading so that the .arx loads when AutoCAD starts. The .arx then loads the associated .vlx file, and voila, demand loading for .vlx files. Instructions for setting up demand loading have been posted on the ‘net in the past (and it is well documented in the ObjectARX SDK), so I won’t describe that here.