<p>The zig-zag pattern are known for this kind of fluke...</p>
<p>I will use Cura to demonstrate, but it's gonna happen on the majority of slicers.</p>
<p>See this example:
<a href="https://i.sstatic.net/uK0sk.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/uK0sk.png" alt="Image showing air gaps when using zig-zag fill for top/bottom layers" /></a></p>
<p>Because nothing is really a circle on a cartesian plane and there's resolution limitations on the real world, the slicer has to account for these and, assuming you are using zig-zag to save time, they are doing what is expected. The Zig-zag pattern is a continuous, fast way to fill the top/bottom layers.</p>
<p>Now, see this lines pattern top layer:
<a href="https://i.sstatic.net/3CzgP.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/3CzgP.png" alt="Image showing smaller air gaps when using lines fill for top/bottom layers" /></a></p>
<p>It has much smaller air gaps. Every time the nozzle finishes a line, it has the chance to reposition itself to make a much smaller gap, just because isn't continuous.</p>
<p>So yeah, the air-gaps are a &quot;feature&quot; for zig-zag patterns, but you can mitigate this effect reducing the line width on top/botton layers.</p>
<p><a href="https://i.sstatic.net/V4zXp.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/V4zXp.png" alt="Image showing kinda-smaller air gaps with zig-zag patterns when reducing the line withd" /></a></p>
<p>It seems that increasing &quot;Skin Overlap Percentage&quot; on cura mitigates this effect too, but i really haven't seen the effects of this setting on a real life object</p>

CC BY-SA 4.0
2021-06-22T09:55:34.673Z
Thanks. The zigzag vs line patterns was only a part of the problem. The 2nd part was that this layer rested on supports only, so the fill, whatever its pattern, didn't have enough surface to "grab on" near the perimeters. If I had switched from zigzag to lines, the air gap would've diminished a bit, but I would've gotten drooping. I solved it with wider, underlying perimeters. I'll keep the line fill in mind as an option. Thanks.
MrSparkly
CC BY-SA 4.0
2021-06-21T22:22:22.893Z
2021-06-21T22:22:22.893Z
Willian Soares
<p><em>Posted as a wiki answer from a comment from the OP to a different <a href="https://3dprinting.stackexchange.com/a/16584">answer</a>.</em></p>
<hr />
<p>The <a href="https://3dprinting.stackexchange.com/a/16584"><code>Zig Zag</code> vs <code>Lines</code> patterns</a> was only a part of the problem. The 2<sup>nd</sup> part was that this layer rested on supports only, so the fill, whatever its pattern, didn't have enough surface to &quot;grab on&quot; near the perimeters. If I had switched from <code>Zig Zag</code> to <code>Lines</code>, the air gap would've diminished a bit, but I would've gotten drooping. I solved it with wider, underlying perimeters.</p>

CC BY-SA 4.0
2021-07-22T08:29:15.690Z
2021-07-22T08:29:15.690Z
0scar
<p>My Tevo Flash works well. Right now, I'm trying to print a thin, disc-like part on supports. The 3 perimeters at the edge of the disc are OK. The dense fill zigzag pattern makes many U-turns near the perimeter. It all looks OK in Simplify3D. But in the printed part, in several spots, the zigzag pattern doesn't reach the perimeters, leaving a ~1 mm gap.</p>
<p>My guess: in those spots, the filament has nothing to grab onto underneath, so the U-turn region is dragged back by the nozzle a bit (away from the perimeters) and/or it droops. I'm using the smallest support res in Simplify 3D: 1 mm. Any options I can try?</p>
<p><a href="https://i.sstatic.net/nxpz1.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/nxpz1.jpg" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2021-06-14T13:36:20.327Z
I think you are right, not enough support. I'm not using the Simplify3D slicer so I cannot answer for this specific software, but in Cura you can create a top layer over the support creating a platform, this helps me much with hot printed filament and support structures, maybe Simplify3D has a similar option. You possibly can also increase the overlap of the infill over the perimeters.
0scar
CC BY-SA 4.0
2021-06-14T15:38:12.993Z
Cura calls this layer an "interface" and offers it for both top and bottom of supports.
Zeiss Ikon
CC BY-SA 4.0
2021-06-14T18:12:45.493Z
Nice sketch, by the way -- not many people have the skill and expend the effort to draw clearly with pen and paper any more.
Zeiss Ikon
CC BY-SA 4.0
2021-06-15T02:57:33.630Z
OK, thanks. What I did: I added a layer of ONLY perimeters, UNDER the ones in the sketch, wider (6 instead of 3), same radius on the outside, but extending more INWARD towards the center. They don't interfere with the function. Now it works, the fill "catches " on the lower perimeters
MrSparkly
<support-structures><infill><simplify3d>
Fill doesn't reach perimeters on supports (Simplify3D)
MrSparkly
# Fill doesn't reach perimeters on supports (Simplify3D)

(Asked by: username_0 on 2021-06-14)

My Tevo Flash works well. Right now, I'm trying to print a thin, disc-like part on supports. The 3 perimeters at the edge of the disc are OK. The dense fill zigzag pattern makes many U-turns near the perimeter. It all looks OK in Simplify3D. But in the printed part, in several spots, the zigzag pattern doesn't reach the perimeters, leaving a ~1 mm gap.

My guess: in those spots, the filament has nothing to grab onto underneath, so the U-turn region is dragged back by the nozzle a bit (away from the perimeters) and/or it droops. I'm using the smallest support res in Simplify 3D: 1 mm. Any options I can try?

[![enter image description here](https://i.sstatic.net/nxpz1.jpg)](https://i.sstatic.net/nxpz1.jpg)

**Tags:** support-structures, infill, simplify3d

> **Comments:**
> **username_1**: I think you are right, not enough support. I'm not using the Simplify3D slicer so I cannot answer for this specific software, but in Cura you can create a top layer over the support creating a platform, this helps me much with hot printed filament and support structures, maybe Simplify3D has a similar option. You possibly can also increase the overlap of the infill over the perimeters.  
> **username_2**: Cura calls this layer an "interface" and offers it for both top and bottom of supports.  
> **username_2**: Nice sketch, by the way -- not many people have the skill and expend the effort to draw clearly with pen and paper any more.  
> **username_0**: OK, thanks. What I did: I added a layer of ONLY perimeters, UNDER the ones in the sketch, wider (6 instead of 3), same radius on the outside, but extending more INWARD towards the center. They don't interfere with the function. Now it works, the fill "catches " on the lower perimeters  

---

## 2 answers

### Answer by username_1 on 2021-07-22. Score: 2 | Accepted answer

*Posted as a wiki answer from a comment from the OP to a different [answer](https://3dprinting.stackexchange.com/a/16584).*

---

The [`Zig Zag` vs `Lines` patterns](https://3dprinting.stackexchange.com/a/16584) was only a part of the problem. The 2nd part was that this layer rested on supports only, so the fill, whatever its pattern, didn't have enough surface to "grab on" near the perimeters. If I had switched from `Zig Zag` to `Lines`, the air gap would've diminished a bit, but I would've gotten drooping. I solved it with wider, underlying perimeters.


---

### Answer by username_3 on 2021-06-21. Score: 1

The zig-zag pattern are known for this kind of fluke...

I will use Cura to demonstrate, but it's gonna happen on the majority of slicers.

See this example:
[![Image showing air gaps when using zig-zag fill for top/bottom layers](https://i.sstatic.net/uK0sk.png)](https://i.sstatic.net/uK0sk.png)

Because nothing is really a circle on a cartesian plane and there's resolution limitations on the real world, the slicer has to account for these and, assuming you are using zig-zag to save time, they are doing what is expected. The Zig-zag pattern is a continuous, fast way to fill the top/bottom layers.

Now, see this lines pattern top layer:
[![Image showing smaller air gaps when using lines fill for top/bottom layers](https://i.sstatic.net/3CzgP.png)](https://i.sstatic.net/3CzgP.png)

It has much smaller air gaps. Every time the nozzle finishes a line, it has the chance to reposition itself to make a much smaller gap, just because isn't continuous.

So yeah, the air-gaps are a "feature" for zig-zag patterns, but you can mitigate this effect reducing the line width on top/botton layers.

[![Image showing kinda-smaller air gaps with zig-zag patterns when reducing the line withd](https://i.sstatic.net/V4zXp.png)](https://i.sstatic.net/V4zXp.png)

It seems that increasing "Skin Overlap Percentage" on cura mitigates this effect too, but i really haven't seen the effects of this setting on a real life object

> **Comments:**
> **username_0**: Thanks. The zigzag vs line patterns was only a part of the problem. The 2nd part was that this layer rested on supports only, so the fill, whatever its pattern, didn't have enough surface to "grab on" near the perimeters. If I had switched from zigzag to lines, the air gap would've diminished a bit, but I would've gotten drooping. I solved it with wider, underlying perimeters. I'll keep the line fill in mind as an option. Thanks.  

---

