How to Make Lisp File for AutoCAD?

Understanding AutoLISP for AutoCAD

AutoLISP is a powerful, dedicated programming language for custom automation and functionality within the AutoCAD environment. This article outlines the procedure for creating a LISP file in AutoCAD 2025 and highlights key aspects of working with LISP routines.

Setting Up the Environment

To begin, launch AutoCAD 2025 and navigate to the “Tools” menu. Here, select “AutoLISP” and then the “Visual LISP Editor.” This opens the Visual LISP Integrated Development Environment (VLISP), where you can create and edit your LISP scripts.

Writing Your First LISP Program

1. Open the Text Editor: In the VLISP window, go to “File” and choose “New” to initiate a new script.

2. Write Code: In the editor area, you can start typing your LISP commands. Ensure that you adhere to the syntax rules of LISP. For instance, a basic routine might look like this:

   lisp
   (defun c:hello ()
   (princ “Hello, AutoCAD!”))

3. Save Your File: Click “File” and then “Save As” to store your file with a .lsp extension. Choose a recognizable name and a directory that is easy to access.

Running the LISP Script in AutoCAD

After you’ve created your LISP file, it’s time to load and execute it:

1. Open AutoCAD Command Line: Type APPLOAD in the command line and press Enter.
2. Load Your Script: In the dialogue that appears, click on the “Browse” button. Navigate to the directory containing your .lsp file, select it, and click “Load.” After a successful load, the file will be available during your current session.
3. Execute the Command: To run your LISP routine, type the name of the command you defined in your code (for example, hello) in the command line and press Enter. If executed correctly, you should see the output.

Adding LISP Files to AutoCAD’s Startup Suite

For routines you would like to run automatically every time you open AutoCAD:

1. Type APPLOAD in the command line.
2. Click on the “Startup Suite” button and then select “Contents.”
3. Click “Add” and navigate to your LISP files to include them in the Startup Suite.
4. After adding your files, click “Close” to finish.

Where to Find Useful LISP Files

Typically, LISP files can be found in the support file directory of AutoCAD, often located in a path similar to: C:\Program Files\Autodesk\AutoCAD 2025\Support. Many existing LISP routines are available online for various functions that you might want to implement in AutoCAD.

Frequently Asked Questions (FAQ)

Can I edit LISP files using any text editor?

Yes, LISP files are ASCII text files, so you can open and edit them with any standard text editor. However, using the Visual LISP Editor is recommended for syntax highlighting and debugging features.

What is the difference between .lsp and .fas files?

The .lsp files are source files containing LISP code written for AutoCAD, while .fas files are compiled versions of these routines, which can run faster when loaded in AutoCAD.

Is AutoCAD LT compatible with LISP routines?

No, AutoCAD LT does not support LISP routines, and the APPLOAD command is not available in this version. Only the full version of AutoCAD supports AutoLISP functionality.