Problem when moving a trace

Layout
1

Hello!

I was trying to drag the bottom part of the red trace on the left (see attachment).
I was expecting it to move only the bottom part as if I would move a wire between pins. But it seems to try to move everything, therefore also moving around pins 69 to 72. Does anybody know a setup that wouldn’t show that kind of behavior?

I’m using the latest version of Kicad (see below).

Even worse: After dragging, I have fixed between the pins, one by one. I tried to drag the second trace, and it has again messed up everything.

Is this a known bug? A feature?

Thanks,

Pascal

MoveLeft
MoveLeft508×875 56.2 KB

Application: KiCad
Version: (5.1.5)-2, release build
Libraries:
wxWidgets 3.0.4
libcurl/7.66.0 OpenSSL/1.1.1d (Schannel) zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.1.1) nghttp2/1.39.2
Platform: Windows 8 (build 9200), 64-bit edition, 64 bit, Little endian, wxMSW
Build Info:
wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8)
Boost: 1.71.0
OpenCASCADE Community Edition: 6.9.1
Curl: 7.66.0
Compiler: GCC 9.2.0 with C++ ABI 1013

Build settings:
USE_WX_GRAPHICS_CONTEXT=OFF
USE_WX_OVERLAY=OFF
KICAD_SCRIPTING=ON
KICAD_SCRIPTING_MODULES=ON
KICAD_SCRIPTING_PYTHON3=OFF
KICAD_SCRIPTING_WXPYTHON=ON
KICAD_SCRIPTING_WXPYTHON_PHOENIX=OFF
KICAD_SCRIPTING_ACTION_MENU=ON
BUILD_GITHUB_PLUGIN=ON
KICAD_USE_OCE=ON
KICAD_USE_OCC=OFF
KICAD_SPICE=ON

2

Not so much a bug, but a quirk of the router. To workaround this you can break that continuous segment of the track in 2 by right clicking on the chosen point on the track and selecting “break track”. If you do it near pad 69 then you will be able to move lower portion of the track without affecting anything above.

2 Likes
3

It’s not a bug, it’s a feature.

The part of KiCad that is responsible for this behavior is called the “Interactive Router” and it’s settings can be influenced with:
Pcbnew / Route / Interactive Router Settings…

For explanation of the settings, open the Pcbnew manual and search for “Router”, which should get you to chapter 9. On my PC the manual is located at:
file:///usr/share/doc/kicad/help/en/pcbnew.html#_options

How much experience do you have with KiCad? I find the Interactive Router a very powerful feature of KiCad, and until someone finally makes an autorouter that really works (For any PCB program, not just KiCad) it is pretty much the best tool for routing boards I have ever used (I admit: I have not used many of these tools).

Over time I’ve learned to accept what the Interactive router does, and worry much less about the tracks looking “beautiful” to the human eye. The electrons really don’t care, and that is all that matters in the end. I even dare say that putting more distance between those tracks wherever possible is a good thing, because it lowers coupling between the tracks.

The Interactive router really shines near the end of your PCB design when you need to squeeze in the last few tracks with some via’s. The Interactive Router just shoves everything aside to make room for that via and track that have to fit in between.

The auto router also has other nice features, such as removing old tracks as you make new tracks. For example, if you draw a straight track segment from next to pad 69 to next to pad 72, then the Interactive router should (depending on settings) remove the whole part with the squiggly lines in between.

A really important, and the most difficult part of working with effectively with the Interactive Router is to give up control a little bit. Stop trying to micro manage each track segment.

If you do not trust the Interactive Router (yet), then make lot’s of backups of your project. I even want to recommend to spend a few hours not with routing the “real” board design, but just to spend the time examining and experimenting with the settings of the Interactive router. Make this a priority above the finishing of your board. Just mess up the tracks of (a copy of) your board. Don’t be afraid of the Interactive Router. When you have a fairly good idea of it’s power and how to use it you will route your boards faster.

The Interactive router is hard to explain in text. Search youtube for the interactive router and you will find some very nice video’s which show you the power it has.

1 Like
4

That “sawtooth” can be seen as a bug because nobody never wants nothing like that. (Triple negation is a negation, right?) Actually it has been changed in 5.99. See also https://gitlab.com/kicad/code/kicad/-/issues/3895.

1 Like
5

OK, I’ll byte.
Why would such a squiggly track be worth spending even a second of thought on? Why would nobody never want nothing like that?

I’ve just stopped caring about such imperfections.
( Matched impedance tracks etc is another chapter).

I am glad this has been “fixed” in 5.99 though. Having less track segments on the PCB is a small advantage. Having less capacitance between tracks usually is also an advantage.

But I admit. after a PCB is fully routed and DRC error free I usually run it over to give it a visual check and still have a tendency to “clean up” such things.

6

Maybe one negation would have been enough. The point is, it’s never needed. So why keep behavior which nobody actually wants. And most layout designers probably don’t like it even if they can stand it.

7

Hello!

you can break that continuous segment of the track in 2 by right clicking
on the chosen point on the track and selecting “break track”.

Good hint! Works perfectly, thanks. If this break could become automatic in
the next versions, it would be great, but in the meantime, it does the job.

Pascal

8

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