Pad-phobic traces

Layout
1

Hello!

I found an oddity when routing traces. Please checked movie.
I would like to route a trace to one pad as indicated by the ratsnest.
Whatever I do, it doesn’t want to stick to the pad. On the other hand, if I start
from the pad, then it works fine.
Any idea of what happens?

Thanks,

Application: KiCad PCB Editor

Version: 6.0.8-f2edbf62ab~116~ubuntu22.04.1, release build

Libraries:
wxWidgets 3.0.5
libcurl/7.81.0 OpenSSL/3.0.2 zlib/1.2.11 brotli/1.0.9 zstd/1.4.8 libidn2/2.3.2 libpsl/0.21.0 (+libidn2/2.3.2) libssh/0.9.6/openssl/zlib nghttp2/1.43.0 librtmp/2.3 OpenLDAP/2.5.13

Platform: Linux 5.15.0-50-generic x86_64, 64 bit, Little endian, wxGTK, ubuntu, wayland

Build Info:
Date: Sep 30 2022 16:52:15
wxWidgets: 3.0.5 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
Boost: 1.74.0
OCC: 7.5.2
Curl: 7.85.0
ngspice: 36
Compiler: GCC 11.2.0 with C++ ABI 1016

Build settings:
KICAD_USE_OCC=ON
KICAD_SPICE=ON

2

Hello again!

Just for info, I found a workaround by tuning the net default sizes. The minimal track size used to be 0.2 for some reason. I don’t know exactly why because I have always been using 0.125, and these days 0.1. By setting it to 0.1, the problem was solved. However, it does not explaines the behavior. There is enough space for the 0.2mm trace, and it refuses to route.

Thanks,

3

I’ve seen that as well, although I don’t recall what version of V6 I was using. You rightly called it out as a bug, I just started from the other pad and thought of it as a quirk.

4

If you can publish the file, or a stripped down version of it which shows the bug, this is worth reporting to the issue database.

5

Looks like a genuine bug. Please PM or publish here a stripped-down layout that demonstrates the problem. We cannot fix it without that.

T.

6

Is there anything on or under the pad?
What does it look like if you: PCB Editor / View / Drawing Mode / Sketch pads

I think I’ve seen similar behavior before with attempts to draw castellated pads, which by definition overlap with the outside perimeter of the PCB. Some external sites that generate footprints draw some lines on the Edge.Cuts layer in the center of a pad, and that could be a reason you can’t reach the pad with a track (It preserves the clearance from the lines on Edge.Cuts).

I do agree with twl though. It looks like a bug, and to fix the underlying issue a test case is needed.

7

Hello!

No, there was nothing under the pad, it’s a plain resistor taken from a standard library and copied to my personal component list. The only thing I usually change is the radius at corners.

Yes, but in this case, how can you explain that it works when drawing from the pad?
And beside this, sorry, I cannot publish the file.

I’m trying to reproduce the bug in a new file right now. Stay tuned!

8

Sometimes there’s coincidence of factors that are hard to reproduce.
There are still two options left:

  • report as confidential so only trusted members are allowed to see the file,
    or
  • strip down the existing design to the point it does not bring any disclosure issues.
9

Hello!

I tried to reproduce the bug in a stripped version of the file, and it doesn’t work. I mean: it works fine,
I cannot reproduce the bug.
Sorry.

10

You can always send us the confidential file via e-mail or create a confidential issue in gitlab.

T.

11

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