CAD Automation Glossary

Plain-English definitions of the terms CAD pros use when writing, buying, or installing automation for AutoCAD, Civil 3D, Revit, and Dynamo. 39 terms.

.

• .addin manifest — The XML file Revit reads at startup to discover and load .NET add-ins from the user's Addins folder.
• .NET plugin — A managed assembly (C#/VB.NET DLL) that uses Autodesk's .NET API to add commands and behaviour to AutoCAD or Civil 3D.

A

• ACAD.lsp — A LISP file AutoCAD looks for on every session start and loads automatically — the standard place to autoload routines.
• acaddoc.lsp — A LISP file AutoCAD loads every time a drawing is opened, used for per-document setup and (defun S::STARTUP).
• APPLOAD — The AutoCAD command that opens a dialog for loading .lsp, .fas, .vlx, .arx, or .dll files into the current session.
• AutoLISP — Autodesk's dialect of LISP, built into AutoCAD since 1986, used to write custom commands and automate drawings.
• AUTOLOAD — Two related AutoCAD mechanisms for loading plugins on demand: the (autoload) LISP function and the auto-load registry/bundle keys used for .NET DLLs.

B

• block attribute — Editable text fields attached to an AutoCAD block reference, used for tags, callouts, and title-block data.

C

• Civil 3D — Autodesk's civil engineering and survey vertical built on top of AutoCAD, adding alignments, surfaces, corridors, and pipe networks.
• command alias — A short keyboard shortcut for an AutoCAD command, defined in acad.pgp (e.g. L → LINE, CO → COPY).
• CommandMethod — The .NET attribute you place on a method to expose it as a typeable AutoCAD command after NETLOAD.
• CUI — The AutoCAD command that opens the Customize User Interface editor, where you edit menus, ribbon, and shortcuts.
• CUIX — AutoCAD's customization file — a zipped XML bundle of menus, ribbon tabs, toolbars, keyboard shortcuts, and the LISP/MNL files they reference.

D

• DCL — Dialog Control Language — a small markup AutoCAD uses to define LISP dialog boxes.
• DesignScript — The textual scripting language Dynamo's code blocks use — a stricter cousin of Python with stronger type safety.
• DWG — Autodesk's proprietary binary drawing format — the file that contains every AutoCAD or Civil 3D drawing.
• Dynamo — Autodesk's visual programming environment, used inside Revit and Civil 3D to automate model and design tasks with node graphs.
• Dynamo node — A single function block in a Dynamo graph — the unit you wire together to build an automation.
• Dynamo Player — A simplified Dynamo runner inside Revit/Civil 3D that lets non-Dynamo users run vetted .dyn graphs by clicking a button.

F

• FAS — A compiled, single-file binary of an AutoLISP/Visual LISP routine. Faster to load and obscures the source code.
• field code — A dynamic text expression inside AutoCAD text or block attribute that auto-evaluates from a drawing property, date, file path, or formula.

I

• IExternalCommand — The Revit .NET interface a class implements to expose a single command button. Implements Execute(...) and returns Result.Succeeded/Failed.

L

• LandXML — An open XML schema for exchanging civil engineering and survey data — surfaces, alignments, parcels — between Civil 3D and other software.
• LISP — A scripting language used to automate AutoCAD by writing routines that issue commands, query drawings, and build custom tools.
• LISP routine — A self-contained AutoLISP program that adds a command or behaviour to AutoCAD — usually one .lsp/.fas file.

M

• MNL file — A LISP file with the same base name as a CUIX/CUI menu, loaded automatically when that menu loads.

N

• NETLOAD — The AutoCAD command that loads a managed .NET plugin DLL into the running session.

O

• ObjectARX — Autodesk's C++ runtime extension SDK for AutoCAD. The lowest-level, highest-performance way to extend AutoCAD.

P

• pyRevit — An open-source framework that runs Python scripts inside Revit and exposes a ribbon for community-built tools.

R

• Reactor — An event handler in AutoCAD that fires when something happens — an object is modified, a command runs, a drawing is saved.
• Revit — Autodesk's Building Information Modeling (BIM) authoring tool. Automated primarily with Dynamo and the Revit .NET API.
• ribbon tab — A horizontal page on AutoCAD's or Revit's ribbon that groups related panels and buttons. Defined in CUIX (AutoCAD) or via the Revit API.

S

• S::STARTUP — A special LISP function name AutoCAD calls automatically after any drawing finishes loading.
• Support File Search Path — The ordered list of folders AutoCAD scans to find LISP, font, menu, and template files.

T

• Trusted Locations — AutoCAD's allow-list of folders that can load executable code (LISP, .NET, ARX) without a security warning.

V

• VBA — Visual Basic for Applications — Autodesk's legacy macro language for AutoCAD. Still supported but no longer the recommended automation path.
• Visual LISP — An extended LISP environment in AutoCAD that adds an IDE, debugger, COM access, and the ability to compile to FAS or VLX.
• VLX — A compiled Visual LISP application that bundles multiple .lsp/.fas files, DCL dialogs, and resources into one file.

X

• Xref — An external reference — a DWG file inserted into another DWG that updates automatically when the source changes.