Thin Gaps in walls filled with small zig-zags

[cp2004 1]

I have an issue with Cura filling objects with thin gaps between walls, where a part is  with tiny zig-zag lines that slow down the print massively. From what I can remember this was an issue since 3.6 as it behaved differently before. This image describes the lines - https://i.redd.it/3ip9ep8ca7c21.png (from a reddit post) and I have had it with this christmas tree file attached below. I can confirm if it is  also an issue in 4.0 as I have downloaded the beta.

I have seen various reports of this issue, it stresses printers frames and drastically slows print time.

[gr5 2,172]

My first though is if you play around with wall thickness you can drastically reduce that gap and it will do two walls instead.  Much faster.  So try 0.7 wall thickness to see if that helps.

 

Anyway, to answer your question, yeah there are a few options that if understood can eliminate this.  I think.  Or maybe that gap is too big?  This "problem" you are talking about has annoyed me a little but not as much as you so I never really did anything about it but I found the discussion on this ticket extremely informative and may give you some ideas of a few things to try:

https://github.com/Ultimaker/Cura/issues/3277

 

But again, maybe your gap is much too big to be affected by the suggestions in this github "issue".

[gr5 2,172]

Oh!  Also there is I think an option for "concentric infill" that may fix this?  I can't see your "percentage infill" in your screen shot but I assume it's less than 50% and this screen shot is "top" or "bottom" infill.  So you can also make the top or bottom shell thinner but then your part will be weaker.

[cp2004 1]

I think you may have linked the wrong ticket, that one is about the fonts in cura 3.2...

Concentric Infill has similar effects, but not so bad. The infill percentage doesn't change this until it is 0%, in which case there is no fill. 

Wall thickness option seems to have no effect. The issue is caused by having a part that is thinner than 2x total wall width, but thicker than 1 line of the wall so it does this strange infill pattern.

Attached is with concentric infill, then changing the wall width to be less, concentric infill. It seems to be a worse issue with the gyroid infill.

Minimum infill area is the only setting that I could see affecting it.

[cp2004 1]

I have found the setting 'Fill gaps between walls, and turned it off. That was the problem here. Maybe something changed with how it behaves in 3.6. It's fixed for now.