Fusion 360 - Fourth axis trace?

I am looking to do trace a series of projected polygons on a bowl mounted on the avid rotary axis, using fusion 360 for the g-code. This seems like such a simple operation, however it seems like fusion doesn’t have this capability, even with the machining extension.

This is a screenshot of the surface I would like to trace curves on:

And the curves to trace:

Multi axis contour seems like it should work, however it doesn’t seem to have an option to limit it to 4th axis, only 3rd and 5th axis.

Does anyone have any tips on either solving this problem in fusion, or another software that could do this? This probably belongs on an autodesk forum, but lots of smart machinists here so I figured I would ask.

Do you have Rhino 8? Something like this is one option:

rotaryTrace.zip (16.2 KB)

Sure do! Nice, thank you.

@Stephen did you write this? Super clean. My grasshopper rotary solver with tool contact point calculations for ballnose finishing was an ungodly spiderweb, ended up crawling back to fusion.

Yes, thanks. I did some CAM work in Python 3 and was pretty happy when the Python 3 block showed up in Grasshopper. Here’s one example why:
opencamlibtest.zip (28.1 KB)

Unfortunately, opencamlib, being a 3-axis library, hard-codes the spindle axis direction to Z. That means rotary traces require rotating the mesh instead of just the axis. The standard way of running a parallel toolpath, rotating for every stepover, takes hours on my laptop. One workaround is to do fewer mesh rotations and machine a region instead of doing a single trace, which is what I’ve included below. Someday I might port the bit/mesh intersection routines into GH so I can make it more efficient for rotary.
opencamlibtest_Rotary.zip (220.2 KB)

I’m still holding off on Fusion’s machining extension. It’s pretty limited for rotary work, and I haven’t needed any of its specific capabilities yet.

In case it’s helpful —
To get packages like opencamlib and numpy in the GH Python 3 environment, I like to run

import sys

within the Python block, look at the Terminal output, find the .rhinocode/py39-rh8/Scripts/ folder, and run pip.exe install numpy, etc. Unfortunately, every Rhino upgrade requires reinstalling packages. Another way is to use the built-in #r: dependency setup. I found that to be clunky, but maybe it’s better now. There’s also now a way to import local Python packages so you can reuse code. Last I checked, if you want to edit external code while GH is open, you have to do

from importlib import reload
import mypackage

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Thanks so much for all these resources. Extremely useful.

I have a working gh script for those tool contact point calcs on a surface, but quite slow for big toolpaths. A python version might run much faster. At some point when I get my time I am going to have to try to integrate the two as well. Please let me know if you make any progress on that capability.

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