Vector printing (G2/G3/G5)

3Dreamer

Hi all,
from some G2/G3 command tests conducted on my machine I noticed that vector printing produce smoother movements and material deposition, leading also to a better surface finish or permitting higher print speeds.

G2/G3 Controlled Arc Move commands are already implemented in the firmware, so I'm here to ask you if there is the possibility to implement also the G5 command for Bézier curves interpretation.

In my opinion it's a good idea to let the machine reach its real print resolution for curved movements, bypassing traditional G1 "pre-segmentation".

Thank you!

Are there slicers that output g-code that isn't segmented? I'm sure the firmware will evolve as we at some point move away from .stl as the intermediate step that remove all curves.

Dougal1957

@bearer it is slated to be in KissSlicer V2 Premium in the very near future just as it will also support direct input of IGES and STEP Files

Kiss

Cool. I'd guess the devs will have a look after the tct trade show and duet3 dust settles.

Hopefully cheap 32bit boards for Marlin and more slicer support will make it a standard feature in the near-ish future which would be great for faster and smoother prints

3Dreamer

Thank you Bearer and Dougal1957 for your answers,

@bearer said in Vector printing (G2/G3/G5):

Are there slicers that output g-code that isn't segmented? I'm sure the firmware will evolve as we at some point move away from .stl as the intermediate step that remove all curves.

Slicers are waiting for Firmwares and Firmwares are waiting for Slicers. Meanwhile FDM print software stagnate and machines are used well under their true capabilities.

Anyway, Marlin firmware already support G5 commands (as experimental feature), while there are some pieces of software on GitHub that try to re-convert G1 movements into G2/G3 true arcs.

Also consider that there are so much people that experiment with their printer and that do not alway use slicers to produce GCode. Sometimes I also use some self hand-coded softwares to generate the desired GCode commands.

While we wait for overtaking STL it would be nice to let experimenters use their hardware at it's maximum capabilities

@Dougal1957 said in Vector printing (G2/G3/G5):

@bearer it is slated to be in KissSlicer V2 Premium in the very near future just as it will also support direct input of IGES and STEP Files

Kiss

As I know there is no guarantee that vector IGES/STEP informations will be translated into G2/G3/G5 instead of G1 commands, and I have very little hope by reading this page: http://www.kisslicer.com/premium-version.html

Thank you!

If its in experimental marlin, and both are open source then nothing stopping you from experimenting.

3Dreamer

@bearer Yes, it is clear, you are right.
Anyway not everyone is an expert programmer, so I think it is legit to kindly ask/suggest for this kind of firmware additions, and this is the main goal of this thread.

I hope that someone into Duet/RepRap firmware development will be able to listen to my suggestion, or point me towards some partial actual solution.

Thank you!

dc42

I've added this to the RRF 3 wishlist.

I took a look at the Github thread on the Marlin implementation, and it says that it uses an algorithm (De Casteljau's algorithm) that it uses doesn't maintain constant speed. That might be acceptable for laser cutters, but it wouldn't be acceptable for a 3D printer.

3Dreamer

Thank you so much dc42!

I am aware of the non constant speed issue that come from the De Casteljau's algorithm implementation, so we need to find a way to let vector printing become a reality in the RRF 3

3Dreamer

@dc42 While at first it seemed the same to me, deepening the question now I think that the Marlin implementation of the experimental G5 feature lead to obtain a sequence of linear segments, so a constant speed during movements.

What made you wrote about non-constant speed?

Thank you so much!

dc42

@3Dreamer said in Vector printing (G2/G3/G5):

What made you wrote about non-constant speed?

Because when I searched for details of the Marlin implementation, that came up as a reported issue. But just because the lengths of the segments are not constant, that doesn't mean that the speed can't be constant. So maybe they fixed it.

3Dreamer

Hi dc42,
just checking to see if there's any news on G5 implementation

Thank you!

dc42

No new yet, but I'll add it for possible inclusion in RRF 3.02.

3Dreamer

Hi @dc42,
is there any chance to see "G5 Bezier curves" implementation in the forthcoming period?
We are almost ready with our experimental slicing software, so it would be nice to test it on our machine ,-)

Thanks you so much for your work!