Constraining patterns around Z to 3-axis movement using 5-axis config

[SerhiiPohorielov]

Hi everyone,

tldr: pattern around Z rotates C axis instead of rotating the toolpath instances

Added 5th B+C axis trunnion to a 3-axis DNM5700 recently, edited the original machine config from HSM library accordingly, plus added a few functional tweaks from previously used 3-axis PP (also from library).

All the 3-axis and 5-axis functions are performing as expected, except patterns around vertical axis.

I still do a lot of 3-axis work on a stationary zero-point plate stationed beside the trunion, and in a normal condition C axis is parallel to Z. 

I have quite a bit of cylindrical parts held in 3-jaw chucks through said zero-point, so the vertical axis of a part also defines XY zero in setup.

When a pattern of some features is created around the same vertical axis, Fusion assumes that the part is also situated exactly at a center of C axis and instead of rotating the toolpath instances themselves, rotates the C axis (which does not carry a part).

Choosing any other axis and/or suitable part feature does not help, Fusion can clearly idenify that my Z axis is collinear to C.

Can anyone point me to a workaround for this? Ideally I would like to be able to use both rotating C axis pattern and a toolpath rotation around arbitrary vertical axis.

Or at least have an option to easily force Fusion to ignore B and C axis.

I can see using separate PP with multiaxis functions disabled as a last resort.

Exact pattern attached, sadly cannot show the part.

Thanks!

[programming2C78B]

Does your post dialogue give you these options? Do you use the Z axis line as your circular rotation point or the select dia on the part itself? 

[SerhiiPohorielov]

Nope, post uses in-built machine configuration, changeable only through .cps file.

I tried defining both setup Z axis and pattern axis in pretty much every combination. It seems to me that Fusion detects their alignment regardless of selected features hierarchy.

[euclidmandd]

@SerhiiPohorielov 

I'm wondering if you ever found a solution to this. I recently updated my postprocessor (Haas NGC UMC 750) and now I'm having this issue. It wasn't an issue on the old post, so I guess I'll just go back to that for now, but it makes me loose a couple other features I liked with the new post.

[matty.fuller]

Should be easily possible by creating a second machine definition that doesn't have the B/C axes configured. This is the approach we take with our VF2SSYT with TRT210, I choose one machine definitition for working on the trunnion and the other for working on the table.

[SerhiiPohorielov]

Unfortunately, I did not as of yet. I`m certain that it is possible to trace the logic behind the C axis output using Autodesk plugin for Visual Studio Code, but I have yet to find sufficitent time to do that.

[a.laasW8M6T]

Hi

Currently you can do this with a post modification(I cant remember exactly where to change it) or By using a 3 axis machine config as @matty.fuller  says.

In the Future you will be able to control this in the pattern itself in Fusion.

I'm not sure exactly when this will be available though

[euclidmandd]

Good to know there's a fix in the pipeline. For now I'm just going to stick with the old post. Most of my programs need 5 axis positioning, so using a 3 axis configuration won't work. in the meantime, if you come across where/how to do that post modification, please let me know.

Have a good one

[a.laasW8M6T · Accepted solution]

@euclidmandd  Pattern rotation preferences are now available in the latest update

See what's new

https://www.autodesk.com/products/fusion-360/blog/april-2026-product-update-whats-new/

[euclidmandd]

@a.laasW8M6T 

Wow, good timing! Thanks for pointing that out. I'll give it a shot next time I'm programming something like that.

[SerhiiPohorielov]

I tried posting rotary pattern with my previous postprocessor using linear preference and it worked, no C-axis output, just planar XY as needed.

Cheers to devs for answering the feedback!