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Arachne slicing

I was wondering if you had looked at the Arachne slicing algorithm which is in Cura 5 and the alpha version of Prusa Slicer 2.5.0. It works much better on gear teeth than the old slicing algorithm. You get a lot fewer of the little tiny lines in the middle of teeth which you worked round by using fancy gears.

5 comments

5 Comments

David Elworthy

Jul 27, 2022

There is an interesting followup to this from Thomas Sanladerer, where he suggests that the Arachne algorithm enables you to get the same precision with a 0.6mm nozzle that you would previously have needed a 0.4mm nozzle for, with a reduction in print times of typically 30%. I've done a few tests (I have a Revo 6), and my experience so far matches his.

Steve

Jul 27, 2022

Replying to

Thanks for posting. Here is the link for others to find the video https://youtu.be/WgXM2zPusXo

It is quite interesting. I am excited to try the new Arachne engine. Most of my clock gears have been heavily optimized to slice without Arachne and I believe they will print better with the classic slicer. However, nearly all other clock parts should work best with Arachne. This includes all of the large slow printing parts. A 30% speedup would make a big difference. It would be even faster with a 0.3mm layer height.

Up until now, I have only used 0.4mm nozzles. I don't even know if I own any 0.6mm nozzles. Maybe a machine with a quick-change nozzle would make me change my mind.

David Elworthy

Jul 27, 2022

Replying to

I switched to the Revo 6 a few months back and it is sooooo easy to change the nozzle. I think I had only done it twice in all the year prior to that as it was such a pain with having to hold the heater block in place. Now it's just unload the filament, unscrew the old one, screw in the new one, ready to go.

Steve

Jul 20, 2022

Yes, I just noticed a video describing the feature in PrusaSlicer 2.5. It looks like a huge improvement. I typically go back and forth between CAD and the slicer to eliminate most of the tiny gap fill bits. The Arachne algorithm might eliminate a few steps. And it should make the gears stronger. I have had a few printed gears where the spokes had a slight separation down the center. The Arachne algorithm should reduce these issues as well.

I will probably wait for the official release to try it out. I use PrusaSlicer since it works so well for Prusa machines.

Steve

Jul 21, 2022

Replying to

I decided to load the alpha3 version to see how the Arachne engine performs. It appears that most of my clock gears slice better with the Arachne setting turned OFF.

I did a test slice of the ratchet from the electromagnetic desk clock and a gear from the 32 day clock.

Original slicer: 2h51m

Arachne slicer: 3h7m

The Arachne engine uses rounded inside corners that leave a small gap to be filled. Changing to 3 perimeters makes it slightly better.

Traditional gears from my first clock work better with the Arachne engine. Here is the classic slicer showing gap fill in every tooth.

And the Arachne slicer. The rounded corners reduce the need for gap fill.

Edit: Overall, I think the Arachne slicer is a great improvement for most designs. The rare cases where it becomes slightly worse are when a design has been deliberately modified to take advantage of the "old" slicer characteristics. As it turns out, I have been optimizing my clock gears for the old slicer. Some of my clock parts, especially the gears, will print better with the Arachne feature disabled. Most other parts will be better using Arachne. If rounded corners could be selectively disabled, then the clock gears would likely print better using Arachne.

Steve