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AutoCAD LISP Routines

Short answer

AutoCAD LISP routines are small AutoLISP programs that add commands to AutoCAD by loading a .lsp, .fas, or .vlx file. Most routines are 50-500 lines, ship as a single file, and load with APPLOAD or the Startup Suite. Browse below — every listing names the commands it adds, the AutoCAD versions supported, and the file format.

What makes a great autocad lisp routines

A great LISP routine ships in compiled .fas or .vlx (faster load, source hidden), defines clearly-named commands (no single-letter command names that collide with built-ins), documents every command in a README, handles odd selection cases without crashing, and explains which system variables it touches.

Most popular LISP routine categories on CAD Exchange

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Frequently asked questions

Do AutoLISP routines work in all AutoCAD versions?

Largely yes — AutoLISP is highly backward and forward compatible. The exception is routines using LISP functions added only in recent AutoCAD releases. Each listing names its tested AutoCAD versions.

Will LISP routines work in AutoCAD LT?

No. AutoCAD LT does not include the LISP interpreter. Full AutoCAD and the verticals (Civil 3D, MEP, etc.) are required.

What's the difference between .lsp, .fas, and .vlx?

.lsp is human-readable source. .fas is compiled bytecode (faster load, source hidden). .vlx is a bundled package of multiple .fas plus DCL/resources. All three load the same way.

Should I prefer .lsp source or .fas compiled?

.fas if you want fastest load and don't need to modify; .lsp if you want to read or adapt the code. Some sellers offer both as 'Source Included' listings.

Install & how-to guides

How to Load a LISP Routine in AutoCAD

Three reliable ways to load .lsp, .fas, and .vlx files into AutoCAD, plus how to add them to the Startup Suite so you never reload again.

How to Auto-Load a LISP Routine When AutoCAD Starts

Four ways to make a LISP routine load automatically — Startup Suite, ACAD.lsp, acaddoc.lsp, and Trusted Locations — and which to pick.

How to Write Your First AutoLISP Routine

Write, save, and load a five-line LISP routine that adds a custom command to AutoCAD.

How to Compile a LISP Routine to FAS

Use Visual LISP to compile your .lsp source into a faster-loading, source-hidden .fas file ready for distribution.

Related categories

Tools, Plugins & LISP Routines for AutoCAD

Buy and download verified AutoCAD automation: AutoLISP routines, .NET plugins, and ObjectARX add-ins. Reviewed by CAD pros, scanned for malware, version-locked to your AutoCAD release.

AutoCAD .NET Plugins (C# / VB.NET)

Verified .NET plugins for AutoCAD and the AutoCAD verticals. NETLOAD-ready DLLs and one-click .bundle installers, with explicit AutoCAD version compatibility on every listing.

Glossary

LISP

A scripting language used to automate AutoCAD by writing routines that issue commands, query drawings, and build custom tools.

AutoLISP

Autodesk's dialect of LISP, built into AutoCAD since 1986, used to write custom commands and automate drawings.

Visual LISP

An extended LISP environment in AutoCAD that adds an IDE, debugger, COM access, and the ability to compile to FAS or VLX.

FAS

A compiled, single-file binary of an AutoLISP/Visual LISP routine. Faster to load and obscures the source code.

VLX

A compiled Visual LISP application that bundles multiple .lsp/.fas files, DCL dialogs, and resources into one file.

APPLOAD

The AutoCAD command that opens a dialog for loading .lsp, .fas, .vlx, .arx, or .dll files into the current session.

LISP routine

A self-contained AutoLISP program that adds a command or behaviour to AutoCAD — usually one .lsp/.fas file.