Why cura stitching two walls together

[Demon85 1]

Hi

 

I'm trying to understand why cura makes these small stitches between walls, when in theory there is no gap.

Here's a picture of it in preview mode:

 

 

When I was printing this I noticed that the printer head was stuttering like hell, and I thought something went wrong with the hardware.. Then checked that section in preview mode, and noticed the small stitches, so the printer was doing what was told it to do..

Some details: cura 4.8. that is a bottom layer in the picture, I made this model in fusion 360. The width of this part should be 2.4 mm as seen in the picture below (printing upside down).

Line width is 0.4 mm (ender 3 v2 btw), so if I'm correct, this should yield exactly 6 lines, but it adds these extra stitches inside.

(First the width of this part was 2.5mm, and I thought this was causing the issue, as there was a gap left of 0.1mm,  it would be logical, but it does the same with 2.4mm)

Sounds like a rounding issue, or I don't know. Btw I started decreasing the width of this part: 2.39 mm same result, and with 2.38 mm there are 6 lines, no stitches.

Why is it doing this, and how can I avoid it?

 

[nallath 1,117]

It's likely caused by rounding errors.

 

We are working on a complete overhaul of the slicing algorithm to resolve this issue. You can find an early version of that here:

 

[Demon85 1]

Yep, issue is gone in the alpha! Thanks!