A block-diagram editor that lives inside Autodesk Fusion.
Plan your system architecture without leaving your CAD environment.
Fusion System Blocks adds a system block diagram palette directly inside Fusion. You draw blocks that represent the subsystems in your product — sensors, motors, PCBs, housings, software modules — and wire them together with typed connections. The diagram saves inside your Fusion document, right next to the 3D model.
Key capabilities:
- Create blocks from electrical, mechanical, and software libraries with 8 supported shapes.
- Connect blocks with typed wires, directional arrows, and optional orthogonal routing.
- Link any block to an actual Fusion component so the diagram and the CAD model stay in sync.
- Save diagrams and named variants inside the Fusion document, then create and restore snapshots from the History tab.
- Run rule checks and requirements verification to catch orphan blocks, interface mismatches, and power-budget issues.
- Export 11 report and artifact formats including BOM, connection matrix, SVG, PDF, and more.
The System Blocks palette, ready for a new diagram.
Most engineering teams document their system architecture in separate tools — Visio, Draw.io, PowerPoint — that immediately fall out of sync with the CAD model. Fusion System Blocks keeps the diagram inside the assembly file so there is one source of truth. When you rename a component in the 3D model, the linked block updates automatically. When a newcomer opens the Fusion document, they see both the physical design and the logical architecture in one place.
Experimental — V0.1.1
Core diagramming, named documents, snapshot history, CAD linking, rule checking, and 11-format exports are implemented and tested. Current workspace baseline: 707 automated tests and 32 in-app diagnostics checks. 16 of 18 milestones are complete; milestone 13 and milestone 15 remain not started. The add-in is usable for personal and academic projects. APIs and file formats may change before v1.0.
- Autodesk Fusion (latest version) on Windows 10/11 or macOS.
- No other dependencies — Fusion bundles its own Python runtime.
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Download the latest release ZIP from the Releases page.
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Unzip it. You will get a single folder called
Fusion_System_Blocks. -
Open Fusion (or restart it if it was already running).
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Go to Utilities → Add-Ins.
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Open Scripts and Add-Ins, switch to the Add-Ins tab, click the + button, and select the extracted
Fusion_System_Blocksfolder. -
Find Fusion System Blocks in the list, select it, and click Run.
Optionally check Run on Startup so it loads every time you open Fusion.
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Manual alternative: copy the folder into the Fusion Add-Ins directory if you prefer a file-based install.
| OS | Path |
|---|---|
| Windows | %APPDATA%\Autodesk\Autodesk Fusion\API\AddIns\ |
| macOS | ~/Library/Application Support/Autodesk/Autodesk Fusion/API/AddIns/ |
That's it — a "System Blocks" button appears in the toolbar. Click it to open the diagram palette.
A system block is a rectangle (or other shape) on the diagram that represents one piece of your product — a motor controller, a chassis, a sensor module, a firmware process, etc. Each block has ports (connection points) and can carry metadata like status, cost, and mass.
- Click the System Blocks button in the Fusion toolbar to open the palette.
- In the ribbon, choose a block type from the Create group (Electrical, Mechanical, or Software).
- The block appears on the canvas. Double-click it to rename it.
- Add a second block the same way.
- Select the first block and press C to enter connection mode, then click the second block. A wire appears between them.
- Press Ctrl+S to save the diagram inside the Fusion document.
An example system diagram with blocks, connections, and hierarchy.
Open Fusion document
→ Open System Blocks palette
→ Add blocks for each subsystem
→ Wire them together
→ Link blocks to CAD components (optional)
→ Run Check Rules to validate
→ Export a report (PDF, BOM, etc.)
→ Save — diagram persists inside the .f3d file
- Quick manual regression plan: docs/FUSION_MANUAL_TEST_PLAN.md
- Full release validation plan: docs/DETAILED_TESTING_DOCUMENTATION.md
- Built-in Fusion self-test: run Run Diagnostics from Utilities → Add-Ins
- Current workspace validation baseline:
707 passing
pytesttests and 32 in-app diagnostics checks
Source code is available under the Fusion System Blocks Community License for personal, academic, and non-commercial use. Commercial use requires a paid license — open an issue to discuss.