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Re: G2/G3 Arc Paths options

Posted: Wed May 04, 2016 7:18 pm
by movingimage
Haven't seen any updates here for a while.

I'd love to see a G2/G3 checkbox. Right now when printing curves, if I want them to be smooth, I can't go over 50mm/sec or every now and then my marlin-based printer will stutter and create ugly surfaces. I'd love to give native arcs a try. If it doesn't work, I'd just switch it off!

Alternatively - if I could tell S3D to make curves with fewer segments (realizing that at some point the print would look faceted)...I could probably find a happy medium between speed/stutter/detail.

Thanks for considering this!

Re: G2/G3 Arc Paths options

Posted: Wed May 04, 2016 9:42 pm
by tenaja
I would like this as a setup option, too. My machines can handle arcs much better than a million lines of code.

Re: G2/G3 Arc Paths options

Posted: Thu May 05, 2016 8:42 am
by Alex Borro
I've talked to S3D support more than one year ago reporting that Marlin can easily handle arc commands and begging to add G2/G3 support into S3D and they didn't give me attention.

Using G2/G3 commands results in WAY BETTER finishing for cylindrical surfaces than millions of small segments..

I don't think it is that difficult to implement..



Re: G2/G3 Arc Paths options

Posted: Thu May 05, 2016 9:24 am
by movingimage
Well, it is certainly up to them to choose what they want to impliment. I'd like to see it as an option, if for no other reason than to test it out. If it worked well for me, it would allow me to go from 50mm/s to 150mm/s or more on parts with curved walls. That would save a ton of time on what is currently a 16hr print!

Re: G2/G3 Arc Paths options

Posted: Thu May 05, 2016 11:06 am
by Cosineadditive
If Simplify doesn't enable this option, we'll release our online utility for post-processing gcode into arcs. It also cleans the file for minimum line segment lengths below a user defined threshold, a super helpful thing for the 32bit controllers.

Re: G2/G3 Arc Paths options

Posted: Thu May 05, 2016 11:27 am
by movingimage

Is this yours?

I've tried it a few times, but can't figure out how to get my code much smaller. Not sure what good e resolution settings are either! :)

If you have an app, could I beta test it?


Re: G2/G3 Arc Paths options

Posted: Wed Feb 26, 2020 4:38 am
by eleven10

I'll add my 2cents as well:

I think right now there is a chicken-egg-problem for support of g2g3 gcode and true cad slicing support. Since stl doesn't support any curved paths there is little gain of implementing G2G3 gcode support in most 3d printer firmwares which further decreases support for this. Until true CAD/nurbs slicing is introduced I suppose two intermediate solutions:

1. support for g2g3 infill code:
since the infill is not defined by the stl true g2g3 commands could be used for infills like gyroid;

2. Support for sliced layer data: since slicing a cad .step file is not quite as easy to implement a first step could be support for some kind of layer / curve based format. Most CAD software has the capability to periodically slice the model in Z direction and export the resulting model as some kind of curves. It would be awesome if slicers could import these and generate stuff like support/infill from these curves, resulting in g2g3 arc gcode. This would give firmware dev an incentive to support g2g3 arcs as well.

Is there any development in this regard going on at s3d?

Re: G2/G3 Arc Paths options

Posted: Sat Jan 30, 2021 2:47 pm
by tenaja
I know this is an old thread, but I have recently started using OctoPrint, and the Arc Welder plugin does this.

Maybe someone with more time than I will be able to adapt it to a Simplify 3d plugin. It has been adapted to Cura already.

Have fun!

Re: G2/G3 Arc Paths options

Posted: Tue Feb 09, 2021 7:30 am
by jmunkki
You can use the scripts tab terminal commands box to enter shell commands to postprocess gcode. This works perfectly for the command line version of Arc Welder. I just did it in about 10 minutes.

If you want to install a binary, you can find them here:

I'm on a Mac and copied the executable to /usr/local/bin/. I tried running it from a terminal window, but had to use the security control panel to allow it to run, because it's not properly signed. It's up to you to decide you want to trust this on your computer.

Once you have it running (you get a help message if you run it without arguments), you just need to add it to the terminal script:

/usr/local/bin/ArcWelder "[output_filepath]"

On a Windows machine, you would have ArcWelder.exe and the path will obviously look different too.

The terminal commands are only run when you save the gcode to a file, so if you would like to preview the modified gcode, you need to open the gcode back into Simplify3D.

Edit: I added quotes around [output_filepath] so that paths or filenames that contain spaces will work.