.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.
An AutoCAD .NET plugin is a managed DLL that references AcDbMgd, AcMgd, AcCoreMgd, and (for Civil 3D) AeccDbMgd/AeccPressureMgd. It defines a class marked with [CommandMethod("MYCMD")] for each command it adds. Plugins load with NETLOAD, or automatically via an AutoCAD bundle or registry auto-load entry. .NET is the most common modern API because it's far easier than ObjectARX and far more capable than LISP — you get the full .NET BCL, NuGet, debugging, and proper exception handling.
Related guides
Load a C# / VB.NET plugin DLL into AutoCAD with NETLOAD, troubleshoot common load errors, and set up auto-load so you don't NETLOAD every session.
Step-by-step install for Civil 3D add-ins, including installer-based bundles, manual NETLOAD, and per-version compatibility checks.
Browse related listings
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.
Verified Civil 3D-specific .NET plugins and AutoLISP routines for civil engineers and land surveyors. Reads and writes first-class Civil 3D objects.
Related terms
The AutoCAD command that loads a managed .NET plugin DLL into the running session.
Two related AutoCAD mechanisms for loading plugins on demand: the (autoload) LISP function and the auto-load registry/bundle keys used for .NET DLLs.
Autodesk's C++ runtime extension SDK for AutoCAD. The lowest-level, highest-performance way to extend AutoCAD.
The .NET attribute you place on a method to expose it as a typeable AutoCAD command after NETLOAD.