topic Re: AirfoilFitter Add-in in Fusion API and Scripts Forum

AirfoilFitter Add-in

m.reeg — Sun, 25 Jan 2026 14:06:37 GMT

Hi all,

There are a number of Add-ins and scripts that read airfoil data from .dat files and create fit-point splines between each data point. This typically results in an excessive number of control points and suboptimal curvature, which can cause issues when creating bodies and surfaces from this geometry.

My add-in tries to address this by fitting a control point spline to the input data, the default is 10 points but that can be increased to improve accuracy as needed.

I've been experimenting with various methods to do this, and the current version is based on the paper "Universal Airfoil Parametrization Using B-Splines" (https://arc.aiaa.org/doi/10.2514/6.2018-3949).

Fusion doesn't really support B-Splines, so I have to abuse them by creating "single-span" B-Splines which admittedly is kind of stupid, but Fusion accepts them as a control point splines and that makes them useful for this application.

I do have a standalone project that creates proper B-Splines and those can be used in pretty much any other CAD-Software, the Fusion Add-In is a spin-off of this project.

The Add-in requires a couple of dependencies and attempts to install them on first run. This seems to work well on Windows but not so much on MacOS, any advice here would be greatly appreciated.

People have got it to work on Macs, but that requires manually installing the dependencies with the correct version of Python.

I have submitted the Add-In to the App Store and it is currently in review.

https://github.com/mr33g/AirfoilFitterFusionAddin/

AirfoilFitter in action

Looking forward to your feedback!

Best,

Michael

Re: AirfoilFitter Add-in

rohit.bapat — Tue, 17 Feb 2026 06:26:20 GMT

Hello @m.reeg

Thank you for posting your great work here. I am yet to check it out but looking at the image attached, something caught my eye.

The curvature at the point where leading edges meet, is not smooth. I was wondering if there is any G1 or G2 constraint added between two leading edges (Splines)?

Thank you

Re: AirfoilFitter Add-in

m.reeg — Tue, 17 Feb 2026 07:14:56 GMT

Hello @rohit.bapat,

The screenshot shows the default settings which are tagnency continuous only, G2 and G3 are available as options.

G1:

G2:

G3:

Regards,

Michael

Re: AirfoilFitter Add-in

m.reeg — Tue, 17 Feb 2026 10:42:28 GMT

The Add-in is available in the App store btw., please download it from there.

https://apps.autodesk.com/FUSION/en/Detail/Index?id=7312110669169312529&appLang=en&os=Win64