Is there software that can take a solid model, e.g. in STEP format, and generate gcode that includes arc/curve commands (G2, G3, G5) when possible?


1 Answer 1


I have been looking at this also. But I can't find a STEP to GCODE software. So the answer to your question is no, not that I'm aware of.

Using STL files, which are approximations of the actual model using triangular shapes, slicers will generate GCODE not including arc codes. I understand that either the printer controller should take care of creating the arc gcode by reading multiple lines in advance and calculate if certain consecutive "straight gcodes" could be replaced by "arc gcodes" or the generated gcode file needs to be pre-processed off-line by separate software, or post processing scripts of slicers.

With respect to reading multiple lines in advance, the 8-bit controller boards are not powerful enough to do all these extra calculations as the different firmwares already utilize the full potential of these boards.

  • $\begingroup$ I guess a gcode postprocessor cold infer arcs/curves from lines, but it seems a shame to have to do this kind of reverse engineering when the source STEP file already has all the arc/curve info... $\endgroup$
    – Roger
    Apr 19, 2018 at 14:18
  • $\begingroup$ I don't know how the STEP files define surfaces/solid geometries, but you could imagine that a slicer needs to slice the model based on whatever orientation that is chosen in the slicer and has to break up the model anyways, so this may be the reason why it is not practical to do. I think that it is not possible, else it would have existed, note that CNC is around for decades. $\endgroup$
    – 0scar
    Apr 19, 2018 at 17:45
  • $\begingroup$ This type of workflow (object model straight to toolpath) does exist for cnc though, doesn't it? I mean for example in Fusion360 can't you generate gcode from a brep object without it being converted to a mesh? $\endgroup$
    – Roger
    Apr 19, 2018 at 21:16

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