How to Use ChatGPT to Create AutoLISP Code for AutoCAD | Automate Drafting | Easily 2026

Open a ChatGPT conversation and describe the drafting action you want automated, the way you'd explain it to a colleague, for example: "create an AutoLISP code that changes a selected object to red." You don't need to know AutoLISP syntax, function names, or color index numbers going in. Mention whether the command should work on one object or a whole selection set, and whether it needs to run once or repeat within the same session. If your task depends on a specific AutoCAD version or a plugin, say so, since AutoLISP behavior varies slightly across versions and is more limited on AutoCAD LT.

ChatGPT returns a code block with a numbered "How to use" section underneath it, in this example five steps covering saving the file, loading it with APPLOAD, and running it by typing RED. Read this before touching AutoCAD: it names the command the script defines and what happens when you run it.

Skim the code itself for which AutoCAD command it calls internally, CHPROP in this case, a legitimate built-in AutoCAD command for changing object properties, and what property it changes. Here that's the color, set to AutoCAD Color Index 1, which is red on AutoCAD's own standard palette.

If the response continues past the first code block, scroll down. ChatGPT sometimes offers a second version, in this case one using ActiveX instead of CHPROP, noting it's generally faster.

Copy the code out of ChatGPT and paste it into a plain text editor. Notepad works fine, since AutoLISP files are just text with a .lsp extension.

Save it with a name that matches the command it defines, like RED.lsp, in a folder you'll remember. AutoCAD doesn't require the filename to match the command, but keeping them aligned saves guesswork once you've built up a few of these.

Type APPLOAD at the command line. This opens a dialog for browsing to and loading LISP files; AutoCAD accepts .lsp, .fas, and .vlx files here, and you can omit the extension when typing a filename.

Navigate to the file you saved and load it. AutoCAD doesn't load custom LISP files automatically on startup. To skip repeating this step every session, click Contents under Startup Suite in the same dialog, add the file there, and it loads automatically going forward.

With the file loaded, type the command name ChatGPT defined, RED here, press enter, select your objects, and check the result. Run this on a throwaway or duplicate drawing the first time, not a live project file. Test a mix of object types if the routine is meant to work broadly; a script that behaves correctly on a line might handle a block reference or a hatch pattern differently.

If the routine doesn't do quite what you need, wrong color, wrong scope, missing a confirmation step, go back to the same ChatGPT conversation and describe the adjustment directly. ChatGPT keeps the context of what it already wrote, so revisions come back faster than a fresh request.