How To Create New Lisp In AutoCAD?

Understanding LISP Programming in AutoCAD

LISP (LISt Processing) is a powerful programming language widely used in AutoCAD to automate repetitive tasks and customize functionalities. This guide will help you create a new LISP file in AutoCAD, allowing you to enhance your productivity.

Steps to Create a New LISP File in AutoCAD

Step 1: Set Up Your Text Editor

Select an appropriate text editor for coding. While you can use any basic text editor, Notepad++ is recommended due to its syntax highlighting features that aid readability. Open the text editor and prepare to write your LISP code.

Step 2: Write Your LISP Code

Start by writing a basic LISP routine. For example, you can create a simple alert function that displays a message. Enter the following code into the text editor:

(defun c:showAlert ()
  (alert "This is my first custom alert in AutoCAD!")
)

This code defines a new command (c:showAlert) that, when executed, will display a message box with your custom text.

Step 3: Save Your LISP File

Once you have written your code, save the file with a .lsp extension. Choose a descriptive name for your file, such as myFirstLISP.lsp. When saving, ensure that you choose "All Files" in the save dialog, so that the text editor does not append a .txt extension.

Step 4: Load the LISP File in AutoCAD

Now that you have created your LISP file, you need to load it into AutoCAD 2025. Follow these steps:

1. Open AutoCAD.
2. Type APPLOAD in the command line and press Enter. This opens the Load/Unload Applications dialog.
3. Click on the “Contents” button under the Startup Suite section.
4. Use the “Add” button to browse to the location where you saved your .lsp file.
5. Select your LISP file (myFirstLISP.lsp) and click the Open button.
6. After adding your routines, click Close to exit the dialog.
7. You can also load your LISP file immediately by selecting it in the Load/Unload Applications dialog and clicking the Load button.

Step 5: Execute Your LISP Command

With the LISP file loaded, you can now run your new command. Simply type showAlert at the command prompt and press Enter. If everything was set up correctly, you should see your alert message.

Common Practices for LISP Development in AutoCAD

• Testing: After writing a LISP routine, always test it within AutoCAD to ensure it functions as intended.
• Comments: Utilize comments in your code to make it easier to understand. You can add comments by prefixing the line with a semicolon (;).
• Version Control: Keep multiple versions of your LISP files if you’re making significant changes, allowing you to revert if necessary.

FAQ

What is the purpose of LISP in AutoCAD?

LISP is used to automate tasks and create custom commands in AutoCAD, enhancing user productivity and enabling the customization of the software to fit specific needs.

Can I edit existing LISP files in AutoCAD?

Yes, you can edit existing LISP files using a text editor like Notepad++. Simply open the .lsp file, make your changes, save it, and reload it in AutoCAD using APPLOAD.

Is there an alternative programming language to LISP for AutoCAD?

Yes, AutoCAD also supports Visual Basic for Applications (VBA), .NET, and other programming languages for customization and automation tasks. Each has its unique capabilities and use cases.