FluidNC Post Processor For Fusion

This repository ships a Fusion post processor tuned for FluidNC-based CNC machines.

Distribution Status

This repository and the v1.0.2 GitHub release currently publish FluidNC.cps publicly.

The Autodesk-derived redistribution status of the Fusion adapter is still unverified. If upstream rights require a change, future releases may move to patch-based packaging and the current adapter artifact may need to be taken down or replaced.

The shipped adapter is a repository-authored rewrite with a repo-owned helper contract. It does not preserve the imported Autodesk helper/property surface in the active FluidNC.cps; old-post comparison and compatibility work live in the local mock-harness tooling instead. Upstream provenance in adapters/fusion/upstream/ is metadata-only and does not include a tracked upstream .cps working copy.

If you only want the post, start with:

• FluidNC.cps
• Install In Fusion

If you want the advanced repo workflow with a Linked Folder, use the install guide above. If you just want a local post file, copy FluidNC.cps into your Fusion posts folder and select it in Fusion's Post dialog.

What Is Different From Stock GRBL

This post adds FluidNC-focused behavior and properties that are not in the stock Fusion GRBL post flow:

• FluidNC-specific post properties for arc tolerance, junction deviation, minimum segment length, and spindle warmup delay
• planner-aware minimum segment filtering to reduce very short linear moves
• split-file output for No splitting, Split by tool, and Split by toolpath
• safer operation restarts and split-file restarts with G53 machine retracts
• safeStartAllOperations support that still works on controllers without optional block support
• inch jobs keep G20 across section starts instead of falling back to metric
• emitted headers echo the FluidNC arc tolerance, junction deviation, and segment filter values used for the post

Default FluidNC Behavior In This Post

• Flood: disabled on purpose and emits no coolant-on code
• Mist: mapped to M7 on and M9 off
• Air: mapped to M8 on and M9 off
• Use coolant: when disabled in Fusion, suppresses all coolant output
• Safe retracts: defaults to G53
• Spindle warmup delay: defaults to 3 seconds
• FluidNC arc tolerance: defaults to 0.002 mm
• FluidNC junction deviation: defaults to 0.01 mm
• Min segment length: defaults to 0.05 mm in code, but can be changed per post run

Recommended Fusion Settings

In the Post dialog:

• set FluidNC arc tolerance (mm) to match your FluidNC arc_tolerance_mm
• use Safe Retracts = G53
• keep Use feed per revolution (G95) disabled
• keep Use coolant enabled if you want Mist or Air commands to output
• set Min segment length (mm) to 0 if you want no filtering, 0.05 for a conservative filter, or 0.1 for a stronger filter

Install In Fusion

Simple local install

1. Download FluidNC.cps.
2. In Fusion, open the Post Library.
3. Import the file into My Posts, or copy it to your local posts folder.
4. Select FluidNC when posting.

Typical local post path on Windows:

C:\Users\<you>\AppData\Roaming\Autodesk\Fusion 360 CAM\Posts\FluidNC.cps

Linked-folder install

If you want the repo copy to be your live Fusion post, follow:

• Install In Fusion

Coolant Mapping Changes You Can Make Locally

Edit one of these:

• your repo copy: adapters/fusion/FluidNC.cps
• your local Fusion copy: C:\Users\<you>\AppData\Roaming\Autodesk\Fusion 360 CAM\Posts\FluidNC.cps

After editing, save the file and restart Fusion or refresh the Post Library.

Example: make Flood output M8 and M9

Change this code:

coolants: [
  {id:COOLANT_FLOOD}, // intentionally no on/off codes - machine has no flood coolant hardware
  {id:COOLANT_MIST, on:7, off:9},
  {id:COOLANT_THROUGH_TOOL},
  {id:COOLANT_AIR, on:8, off:9},
  {id:COOLANT_AIR_THROUGH_TOOL},
  {id:COOLANT_SUCTION},
  {id:COOLANT_FLOOD_MIST},
  {id:COOLANT_FLOOD_THROUGH_TOOL},
  {id:COOLANT_OFF, off:9}
],

To this code:

coolants: [
  {id:COOLANT_FLOOD, on:8, off:9},
  {id:COOLANT_MIST, on:7, off:9},
  {id:COOLANT_THROUGH_TOOL},
  {id:COOLANT_AIR, on:8, off:9},
  {id:COOLANT_AIR_THROUGH_TOOL},
  {id:COOLANT_SUCTION},
  {id:COOLANT_FLOOD_MIST},
  {id:COOLANT_FLOOD_THROUGH_TOOL},
  {id:COOLANT_OFF, off:9}
],

Example: swap Air and Mist

Change this code:

{id:COOLANT_MIST, on:7, off:9},
{id:COOLANT_AIR, on:8, off:9},

To this code:

{id:COOLANT_MIST, on:8, off:9},
{id:COOLANT_AIR, on:7, off:9},

Example: disable all coolant output without editing code

In Fusion's Post dialog:

• leave your tool coolant set however you want
• set Use coolant to off

That suppresses all coolant commands from the post.

What Has Been Validated

The current post has captured regression fixtures for:

• inch jobs
• multi-tool jobs
• split-file jobs
• dense micro-segment jobs

These are stored under fixtures/expected/fusion and checked by:

• Test-FixtureCaptures.ps1

Next Steps

The next major expansion is tracked in:

• Phase 5 Roadmap

That roadmap keeps the repo on a fixture-first path, starting with 3-axis completion and the embedded profile model, then expanding through indexed 3+2, probing, and simultaneous 5-axis support. See the roadmap for delivery order and slice details.

Need The Developer Docs

If you are contributing or modifying the post itself, start here:

• Install In Fusion
• Testing
• Fusion Adapter Notes

For provenance and upstream baseline notes without a tracked copy of the imported post source, see:

• Fusion Upstream Baseline