Instruction on the usage of acad.lsp
(It works for other versions (2000 and later) of AutoCAD and verticals as well)
AutoCAD is normally not supplied with the user-defined startup file acad.lsp; you create (Notepad can be used) and maintain the file yourself. You can create an acad.lsp file if you regularly use specific AutoLISP routines. When you start AutoCAD, it searches the support file search path for an acad.lsp file. If an acad.lsp file is found, it is loaded into memory.
The acad.lsp file is loaded at each drawing session startup when AutoCAD is
launched. Because the acad.lsp file is intended to be used for
application-specific startup routines, all functions and variables defined in an
acad.lsp file are only available in the first drawing. You will probably want to
move routines that should be available in all documents from your acad.lsp file
into the acaddoc.lsp file.
Warning! Do not modify the reserved startup file acadYEAR.lsp
(acad2000.lsp, acad2000i.lsp acad2002.lsp, acad2004.lsp, acad2005.lsp,
acad2006.lsp, acad2007.lsp, acad2008.lsp, acad2009.lsp, acad2010.lsp,
acad2011.lsp). Autodesk provides this file, which contains AutoLISP defined functions that are required
by AutoCAD. This file is loaded into memory immediately before the acad.lsp file
How to create acad.lsp if it does not exist
In the folder where you want to save acad.lsp right click and select New>Text Document. Change the name to acad.lsp. Now you should be able to double click on the file and typically edit it in Notepad.
Or start Notepad, edit, save, ready.
Examples on location for acad.lsp
C:\Program Files\AutoCAD 2008\Support
C:\Documents and Settings\<loginname>\Application Data\Autodesk\AutoCAD
If you want to find folders that are searched by AutoCAD run the OPTIONS command and look at the Files tab and at the Support File Search Path.
Load order of files in AutoCAD
Files in acad.rx
This applies to AutoCAD 2000, AutoCAD 2000i, AutoCAD 2002, AutoCAD 2004, AutoCAD 2005, AutoCAD 2006, AutoCAD 2007, AutoCAD 2008, AutoCAD 2009, AutoCAD 2010, AutoCAD 2011, AutoCAD 2012, AutoCAD 2013
Update related to AutoCAD 2013 SP1: AutoLISP and VBA Security Controls in AutoCAD 2013 SP1. New /nolisp Startup Switch. LISPENABLED, AUTOLOAD, AUTOLOADPATH system variable added.
The acad2013.lsp and acad2013doc.lsp files will now be loaded only from
their default installation folders: