1 Topic by NogginBoink

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Topic: Slic3r arc support?

I've read that Slic3r is able to detect arcs in .stl files and output appropriate G-code with arc commands. I created a model in Sketchup that's basically a rectangle with an arc on one end. I had Slic3r generate G-code and I've noticed that the arcs are all piecewise linear steps.

Do I have to do something special to get Slic3r to generate arcs in the G-code?

2 Reply by Rincewind

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Re: Slic3r arc support?

NogginBoink wrote:

Do I have to do something special to get Slic3r to generate arcs in the G-code?

You should call Slic3r with the --gcode-arc option, but I haven't found any report of good results so far. But I'm planning to try as well.

3 Reply by Rincewind

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Re: Slic3r arc support?

Rincewind wrote:
NogginBoink wrote:

Do I have to do something special to get Slic3r to generate arcs in the G-code?

You should call Slic3r with the --gcode-arc option, but I haven't found any report of good results so far. But I'm planning to try as well.

Update: tried yesterday, it doesn't work. Seems that the feature is not being developed right now. Does anybody know of a slier that can generate G2/G3 commands?

4 Reply by mm2tts

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Re: Slic3r arc support?

I did not know this was possible. Are you saying that the gcode would be similar to what machine tools use for tool paths? My only experience was watching some tool paths being written in our modelshop 15 years ago with Mastercam. These paths were created from Nurbs surface data (no stl's needed). Sounds like a slicer that could slice a nurbs surface model would generate this kind of code rather than the choppy results from an stl.

5 Reply by Rincewind

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Re: Slic3r arc support?

mm2tts wrote:

I did not know this was possible. Are you saying that the gcode would be similar to what machine tools use for tool paths?

Yes I guess so, after all the GCode is a general-purpose protocol that is also used in CNC machines. The Marlin firmware supports arcs, but I have yet to find a slicer that is able to detect arcs and generate the right commands. I would imagine that professional printers have some support for this.

6 Reply by mm2tts

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Re: Slic3r arc support?

It is a big job to try and create Nurbs from polygonal data. SolidWorks has some scanned data conversion tools, but they are major work to use and always have to be cleaned up. I doubt that any opensource slicer software is going to be up to the task.

The trick would be for the slicer to accept and slice the Nurbs data natively, like CAM software does, rather than having to go through an STL transfer.