AutoLISP
Autodesk's dialect of LISP, built into AutoCAD since 1986, used to write custom commands and automate drawings.
AutoLISP is the dialect of LISP that ships with AutoCAD, Civil 3D, and other AutoCAD verticals. It exposes the AutoCAD command line and entity database, so AutoLISP code can issue any command a user can type and inspect or modify any object in the drawing. AutoLISP files use the .lsp extension and load with the APPLOAD command or by being listed in ACAD.lsp / acaddoc.lsp. AutoLISP is the most common entry point for CAD pros writing their first automation because it requires no compiler and runs immediately.
Related guides
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.
Four ways to make a LISP routine load automatically — Startup Suite, ACAD.lsp, acaddoc.lsp, and Trusted Locations — and which to pick.
Browse related listings
Related terms
A scripting language used to automate AutoCAD by writing routines that issue commands, query drawings, and build custom tools.
An extended LISP environment in AutoCAD that adds an IDE, debugger, COM access, and the ability to compile to FAS or VLX.
A compiled, single-file binary of an AutoLISP/Visual LISP routine. Faster to load and obscures the source code.
A compiled Visual LISP application that bundles multiple .lsp/.fas files, DCL dialogs, and resources into one file.
A LISP file AutoCAD loads every time a drawing is opened, used for per-document setup and (defun S::STARTUP).