Hosts AutoCAD

AutoCAD Features

AutoCAD (and its vertical products: Civil 3D, Plant 3D, Architecture, MEP, Electrical, Mechanical, Map 3D) is a fully supported host in RevitDevTool v3.0.

Supported Verticals

The AcadDevTool add-in loads in all AutoCAD-family products:

Product	Registry Detection	Pipe Prefix
AutoCAD	ACAD-*001	AutoCad
Civil 3D	ACAD-*003	Civil3D
Plant 3D	ACAD-*016	Plant3D
AutoCAD Architecture	ACAD-*004	Product-specific
AutoCAD MEP	ACAD-*005	Product-specific
AutoCAD Electrical	ACAD-*006	Product-specific
AutoCAD Mechanical	ACAD-*012	Product-specific
AutoCAD Map 3D	ACAD-*014	Product-specific

Feature Parity with Revit

Feature	Revit	AutoCAD Family	Notes
Python 3.13	Full	Full	Same PythonNet/Pixi environment
PEP 723 dependencies	Full	Full	Auto-install via Pixi
VSCode debugging	Full	Full	debugpy integration
C# / Assembly execution	Full	Full	IExternalCommand discovery
F# scripts	Full	Full	Roslyn-based
Logging panel	Full	Full	Multi-sink, color keywords
MCP tools (standalone)	Full	Full	Host discovery, launch, open model
MCP tools (in-host)	Full	Full	execute_csharp_code, open_document
PyTest bridge	Full	Full	Multi-host client plugin
DirectContext3D visualization	Full	N/A	Revit-only rendering API
Geometry trace interception	Full	N/A	Revit-only log routing
Command Browser	Full	Not yet	Planned

API Differences from Revit

No __revit__ Builtin

Revit injects __revit__ (a UIApplication instance) into the Python scope. AutoCAD does not — instead use the static Application class:

from Autodesk.AutoCAD.ApplicationServices.Core import Application

doc = Application.DocumentManager.MdiActiveDocument
db = doc.Database
editor = doc.Editor

Transaction Pattern

AutoCAD uses TransactionManager.StartTransaction() (similar to Revit but different API):

from Autodesk.AutoCAD.DatabaseServices import OpenMode

tr = db.TransactionManager.StartTransaction()
try:
    bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead)
    # ... work with database objects ...
    tr.Commit()
except Exception:
    tr.Abort()
    raise
finally:
    tr.Dispose()

State Attribute

Both Revit and AutoCAD hosts use sys.__devtool__ as the unified Python state attribute for the DevTools platform.

Running Python Scripts

Create a .script.py file with PEP 723 dependencies:

# /// script
# dependencies = ["tabulate>=0.9"]
# ///

from Autodesk.AutoCAD.ApplicationServices.Core import Application
from Autodesk.AutoCAD.DatabaseServices import LayerTable, OpenMode
from tabulate import tabulate

doc = Application.DocumentManager.MdiActiveDocument
db = doc.Database

with doc.LockDocument():
    tr = db.TransactionManager.StartTransaction()
    try:
        lt = tr.GetObject(db.LayerTableId, OpenMode.ForRead)
        rows = []
        for oid in lt:
            ltr = tr.GetObject(oid, OpenMode.ForRead)
            rows.append([ltr.Name, "On" if not ltr.IsOff else "Off"])
        tr.Commit()
    finally:
        tr.Dispose()

print(tabulate(rows, headers=["Layer", "Status"]))

Running PyTest Tests

See PyTest Bridge for multi-host testing setup. Configure pyproject.toml:

[tool.pytest.ini_options]
host_name = "autocad"
host_version = "2026"

MCP Integration

The standalone MCP server auto-discovers running AutoCAD instances. All built-in tools work with AutoCAD hosts:

# AI assistant can:
- List running AutoCAD instances
- Launch a new AutoCAD instance
- Open a DWG file
- Execute C# code in AutoCAD

See Also

• Civil 3D Features — Civil 3D-specific APIs and workflows
• Host Support — full feature matrix
• AutoCAD C# Demo — C# example