Self intersecting polygons not allowed

Layout
1

Hi experts,
I am trying to draw fill zones on B-CU. While drawing the fill-Zone boundary (Polygon??) aound the edge-cut using “Add filled Zone” tool, an error message stating “Self intersecting polygons are not allowed” appears at the end of the boundary drawing (i.e. where the start and the end-point of drawing meet).

The same problem occurs when I try to draw fill zones on the F-CU.

Could someone tell me what am I doing wrong here please?

For your reference, I have attached the “Version info”, the “pcb” and the “cache.lib” files here.
Best regards
200914 scratch_circuits.kicad_pcb (121.8 KB) 200914 scratch_circuits-cache.lib (13.2 KB) KiCad Version Info.docx (12.2 KB)

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It means that edges of the zone are crossing another edge of the polygon outline.

It means that this zone is OK:

image
image737×506 16.9 KB

But this zone is not:

image
image823×539 21 KB

In the second screenshot the outline of the zone is intersecting itself on the left side of the PCB.

Another note:
You’ve drawn two polygons on the Edge.Cuts layer. There should be only one PCB outline on Edge.Cuts, or you’ll have trouble to have your board manufactured.

1 Like
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Get rid of that triangular loop on the LHS of the board.

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Do you mean the screenshot I posted as an example to show what goes wrong with the “Self intersecting polygons"?

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After commenting it occurred to me that you made up the example since the OP posted project files, not screenshots, and I’m loath to load other people’s projects, which cannot be done if I’m not at my workstation.

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Hi paulvdh and Kenyapcamau

Thanks for your fast response.
I still need to learn a lot about KiCad. If possible, could you kindly point me towards some artikel, blog or FAQ dealing with topics like copper pouring and or intersecting zones please?

@pauvdh
There should be only one PCB outline on Edge.Cuts, or you’ll have trouble to have your board manufactured.

if you mean the PCB outline with 4 M3 screw holes at the corners above the circuit borad, yes, I will delete that. That board outline was drawn just to estimate the approximate pcb size for the actual circuit below for which I had reported “intersecting polygons” problem.

@ kenyapcomau
Get rid of that triangular loop on the LHS of the board.

Could you kindly point out as to which “triangular loop on the LHS” do you mean please?

Thanks and best regards

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“Self-intersecting polygon” doesn’t need an article. But here’s a screencast from version 5.99 which hopefully clarifies it a bit. There seems to be some bug in filling, but you can see how the polygon intersects and when it’s accepted, it has actually been changed to two distinct polygons.

screencast_polygon-2020-10-01_18.47.52

EDIT: I actually found a bug in both 5.1 and 5.99. But anyways it should show what intersecting polygon means.

1 Like
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Hi eelik,
Many thanks. This demo video is quite interesting and I think now I understand a bit better what “self-intersecting polygons” are and how they come into being.
Best regards
starter99

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