Civil 3D MCP Server — TCCE edition

An MCP (Model Context Protocol) server that lets Claude work inside Autodesk Civil 3D 2027 through natural language: read and draw geometry, model roads, compute earthwork and manage styles.

This is TCCE's fork of barbosaihan/civil3d-mcp. It adds:

• Support for Civil 3D 2027 (.NET 10).

• Fixes so the project compiles.

• Six new tool groups: blocks, hatches, road design, styles, earthwork, and surface sampling.

Status: the plugin compiles against the Civil 3D 2027 API. Tools marked (to verify) below have not yet been fully tested on a real drawing. Try them on a test drawing first.

Architecture

┌──────────────┐   stdio   ┌───────────────────┐   TCP / JSON-RPC   ┌────────────────────┐
│    Claude    │ ◄───────► │  MCP Server (TS)  │ ◄────────────────► │  Civil 3D Plugin   │
│  (desktop)   │           │  Node.js          │     port 8080      │  (.NET 10, C#)     │
└──────────────┘           └───────────────────┘                    └─────────┬──────────┘
                                                                              │
                                                                       Civil 3D .NET API

1. MCP Server (TypeScript/Node.js): talks to Claude over the MCP protocol.

2. Civil 3D Plugin (C#): runs inside Civil 3D and calls the Civil 3D API.

Related MCP server: Civil3D MCP Server

Tools

Original tools

Some original actions still return planned:

• In civil3d_alignment and civil3d_profile: create. Use civil3d_road instead.

• In civil3d_surface: add_breakline, add_boundary, extract_contours. Use civil3d_earthwork for the first two.

• In civil3d_corridor: corridor surfaces and volumes. Use civil3d_earthwork instead.

TCCE tools

Notes

• Pads: the Civil 3D .NET API cannot create Grading objects. create_pad computes the daylight line geometrically by projecting the slope from each edge point, with ray fans at convex corners. It draws the pad edge and the daylight as 3D polylines (layer C-GRAD-PAD) and builds a TIN surface from them.

• Volumes: results are in drawing units³. The CY values assume feet. cutFactor multiplies cut (swell) and fillFactor multiplies fill (compaction).

• Styles: collections are addressed by path, e.g. SurfaceStyles or LabelStyles.AlignmentLabelStyles.MajorStationLabelStyles. Properties are addressed by path too, e.g. Text.Height or General.Visible. Copy a style (create_style with copyFrom) before editing a shared one.

Suggested road workflow

list_styles → create_alignment_by_pis → set_alignment_design → create_surface_profile (EG)
→ create_profile_view → create_layout_profile → check_design → apply_superelevation
→ create_assembly → create_corridor (target EG) → earthwork corridor_surfaces (Top/Datum)
→ create_sample_lines → create_section_views → earthwork section_volumes (EG vs Datum)

Requirements

Setup

1. Build the MCP server

git clone https://github.com/JhulVF/Civil3d-mcp-tcce.git
cd Civil3d-mcp-tcce
npm install
npm run build

2. Build the Civil 3D plugin

Copy the 5 Autodesk DLLs into C_References\. They are proprietary and are not included in the repository.

$repo = "$PWD"
$src  = "C:\Program Files\Autodesk\AutoCAD 2027"
"accoremgd","AcDbMgd","acmgd","AecBaseMgd","AeccDbMgd" | % {
  $f = Get-ChildItem $src -Recurse -Filter "$_.dll" -ErrorAction SilentlyContinue | Select-Object -First 1
  Copy-Item $f.FullName "$repo\C_References\"; "OK  $($f.Name)"
}
cd plugin\Civil3dMcpPlugin
dotnet build

The plugin is written to plugin\Civil3dMcpPlugin\bin\Debug\net10.0-windows\Civil3dMcpPlugin.dll.

Civil 3D 2025/2026: these versions use .NET 8. In Civil3dMcpPlugin.csproj, change net10.0-windows to net8.0-windows and install the .NET 8 SDK.

3. Load the plugin in Civil 3D

1. Open Civil 3D with any drawing.

2. Type NETLOAD and select the DLL. Choose Always Load if prompted.

3. Run C3DMCPSTATUS. It should report listener running: True.

To load the plugin automatically, run APPLOAD → Startup Suite → add the DLL.

4. Configure Claude Desktop

Add the server to %APPDATA%\Claude\claude_desktop_config.json inside "mcpServers":

"civil3d": {
  "command": "node",
  "args": ["C:\\path\\to\\Civil3d-mcp-tcce\\build\\index.js"]
}

Fully quit Claude (tray icon → Quit), reopen it and start a new task.

Updating

After pulling changes, rebuild both parts. Close Civil 3D first, because it locks the DLL.

git pull
npm run build
cd plugin\Civil3dMcpPlugin; dotnet build

Then reload the plugin with NETLOAD, quit and reopen Claude, and start a new task.

Environment variables

The plugin port is hard-coded to 8080 in PluginRuntime.cs. If another add-in (e.g. a Revit MCP) uses 8080, change Port there and set CIVIL3D_PORT to the same value in the Claude config.

Plugin commands

Changes from upstream

• The plugin targets .NET 10 for Civil 3D 2027.

• Added the missing using Autodesk.Civil.ApplicationServices; to the Pipe, Surface, Alignment and Corridor command files.

• Replaced APIs that don't exist:

  • GetCorridorIds() → CorridorCollection.

  • ActiveProduct?.Name → ActiveProduct.ToString().

  • TinSurface.GetVolumeProperties → a temporary TinVolumeSurface.

• Added the TCCE tools listed above.

License

MIT. See LICENSE. Original work by barbosaihan; TCCE additions © TCCE.