Sweet Home 3D MCP Plugin

A plugin for Sweet Home 3D that embeds an MCP (Model Context Protocol) server directly inside the application. Lets Claude and other AI assistants control Sweet Home 3D over HTTP — create walls, place furniture, render photos, and more — without any external proxy or separate server process.

Claude Desktop / Claude Code
         │  HTTP (JSON-RPC 2.0)
         ▼
┌─────────────────────────────────────┐
│  Sweet Home 3D  +  MCP Plugin       │
│  Built-in HTTP server on port 9877  │
│  http://127.0.0.1:9877/mcp         │
└─────────────────────────────────────┘

Screenshots

Requirements

Requirement	Version
Sweet Home 3D	6.0 or newer
Java (bundled with SH3D or system)	11 or newer

Note: Sweet Home 3D ships with a bundled JRE. Make sure it is Java 11+. Very old SH3D builds (32-bit Windows installer with JRE 1.8) will silently fail to load the plugin due to UnsupportedClassVersionError.

Installation

Step 1. Download the latest .sh3p file from Releases.

Step 2. Copy it to your Sweet Home 3D plugins folder:

OS	Plugins folder
Windows	%APPDATA%\eTeks\Sweet Home 3D\plugins\
macOS	~/Library/Application Support/eTeks/Sweet Home 3D/plugins/
Linux	~/.sweethome3d/plugins/

Step 3. (Re)start Sweet Home 3D. The MCP server starts automatically on port 9877.

You can verify it is running: Tools → MCP Server... shows the server status.

Claude Configuration

Add to your Claude Desktop claude_desktop_config.json:

{
  "mcpServers": {
    "sweethome3d": {
      "type": "http",
      "url": "http://localhost:9877/mcp"
    }
  }
}

For Claude Code, create .mcp.json in your project directory:

{
  "mcpServers": {
    "sweethome3d": {
      "type": "http",
      "url": "http://localhost:9877/mcp"
    }
  }
}

The plugin also has a built-in "Auto-configure Claude Desktop" button in Tools → MCP Server... that writes this config automatically.

Available Commands

42 commands across 12 categories.

Scene

Command	Description
get_state	Full scene state: walls, furniture, rooms, camera, labels, levels
clear_scene	Remove all objects from the scene

Walls

Command	Description
create_wall	Single wall between two points
create_walls	Rectangular room (4 connected walls)
modify_wall	Change height, thickness, color, arc, coordinates
delete_wall	Delete wall by ID
connect_walls	Connect two walls for correct corner rendering

Rooms

Command	Description
create_room_polygon	Room from an array of polygon points
modify_room	Change name, floor/ceiling color, visibility
delete_room	Delete room by ID

Furniture

Command	Description
list_categories	All furniture catalog categories with item counts
list_furniture_catalog	Browse catalog; filter by name, category, or type
place_furniture	Place a catalog item in the scene
modify_furniture	Move, rotate, resize, recolor furniture by ID
delete_furniture	Delete furniture by ID
duplicate_objects	Duplicate one or more objects by ID
group_furniture	Group multiple pieces into one object
ungroup_furniture	Split a group back into individual pieces

Doors & Windows

... View full README on GitHub