FusionOrphanBodyFinder

A Fusion 360 add-in that finds and fixes "orphan bodies" — loose BRepBodies sitting directly inside components that also contain subcomponents.

The Problem

In well-organized Fusion 360 designs, every "Body" lives inside its own component. But it's easy to accidentally leave bodies at the wrong level of the hierarchy — for example, a component that has both child subcomponents and direct bodies. These "orphan bodies" make it harder to manage visibility, materials, joints, and manufacturing outputs.

This add-in scans your entire design tree, flags every component with orphan bodies, and offers to automatically wrap each one in its own new subcomponent.

Installation

macOS:

cd ~/Library/Application\ Support/Autodesk/Autodesk\ Fusion\ 360/API/AddIns/
git clone https://github.com/erikbuild/FusionOrphanBodyFinder.git

Windows: Download or clone this repository, then copy the FusionOrphanBodyFinder folder to your Fusion 360 add-ins directory:

%AppData%\Autodesk\Autodesk Fusion 360\API\AddIns\

Then in Fusion 360:

1. Go to UTILITIES > ADD-INS (or press Shift+S)
2. Select the Add-Ins tab
3. Find FusionOrphanBodyFinder in the list and click Run

A "Find Orphan Bodies" button will appear in the INSPECT toolbar panel.

Configuration

The add-in reads settings from config.json in the add-in directory. If the file is missing, defaults are used.

{
    "use_custom_panel": false,
    "panel_id": "CustomPlugins_Panel",
    "panel_name": "CUSTOM PLUGINS"
}

Setting	Default	Description
use_custom_panel	false	When true, creates a dedicated toolbar panel in the Solid tab instead of using the built-in Inspect panel.
panel_id	"Custom_Panel"	Internal ID for the custom panel.
panel_name	"MY CUSTOM PLUGINS"	Display name shown in the toolbar for the custom panel.

The panel_id and panel_name settings are only used when use_custom_panel is true. When false, the button appears in the Inspect panel as usual.

Usage

1. Click "Find Orphan Bodies" in the INSPECT panel

2. A dialog appears with a single option: Include Root Component (checked by default). Uncheck this if you want to ignore orphan bodies in the top-level root component. Click OK.

3. The add-in scans every component in the design. For each component that has both child occurrences and direct bodies, you'll see a prompt:

   Component 'Bracket Assembly' contains 2 orphan bodies: [Body1, Body2]

   Move to new subcomponents?

   • Yes — For each body, an input box lets you rename it (defaults to the parent component name). The body is then moved into a new child component with that name.
   • No — Skip this component and move on to the next.
   • Cancel — Stop the entire operation.

4. When finished, a summary message shows how many bodies were moved across how many components.

What Gets Flagged

Component contents	Flagged?
Only bodies, no subcomponents	No
Only subcomponents, no bodies	No
Both bodies and subcomponents	Yes

What "Fix" Does

For each orphan body in a flagged component:

1. Prompts you to name the body (and its new component)
2. Creates a new child component with an identity transform
3. Names the new component after your input
4. Moves the body into the new component via moveToComponent

The body's position in 3D space is preserved — only its location in the browser tree changes.

Project Structure

FusionOrphanBodyFinder/
├── FusionOrphanBodyFinder.py        # Add-in source code
├── FusionOrphanBodyFinder.manifest  # Fusion 360 add-in manifest
├── config.json                      # Optional panel configuration
├── resources/
│   ├── 16x16.png                    # Toolbar icons
│   ├── 32x32.png
│   └── 64x64.png
├── LICENSE
└── README.md

License

MIT + Commons Clause

Made By

@erikbuild