A via can't be placed without any waning or violation message

Hi all,

When I do a layout with a board, I found that some vias can’t be placed, and I haven’t found any warning message or violation message.

Here is a video to show you how it is:

And here is the source file of the PCB:
Example.kicad_pcb (163.0 KB)

You are trying to place a via on the bottom layer track and the via clearance is interfering with the top layer track clearance.

Hi JMK,

Sorry, I don’t think so.

If you look at the video carefully, you will see that the clearance display has been turned on and the via is not in any track clearance area.

And if there is a clearance violation, I will get a warning message on the top of PCB editor, but I haven’t got any message on it.

The video can’t be looked at carefully without eyes aching. You could have at least turned other than copper and edge layers off. And it could pay back to learn to use a screen recorder (screencast).

  • I also guess your wanted via-destination violates the clearance of the copper track (so I second @jmk)
  • you need to provide not only the pcb-file, but the complete zipped kicad project (Kicad main project manager–>File–>Archive project). That’s because the current board-settings, all board constraints and all additionall custom rules are saved in the project-files, not in the board file.
  • the via-placement depends on the current selected grid-size. If your grid-setting is to coarse you could try again with a finer grid
  • you could also try to use Shift and CTRL modifier key - this disables both grid-snapping and track-snapping
  • this is another reason to use a screenrecorder (as recommended by eelik) - so we could see your settings during via-placement

Hi MF,

Thanks for your reply.

First all, this is my companies project, so I don’t want to offer the whole project for business security policy.

Before upload the PCB file I have open the PCB file and re-place the via and the same issue occurred again, so I only upload the PCB file.

I didn’t take a screenrecord video but use cell phone to record the video because I want to record the voice, if only a screen record, you will only see that a via is stay there, you will not know I have hit the mouse button for several times.

And now, I have some new discoveries.

I found that I can only place a via on a track which is in vertical direction or in horizental direction.

Here is another project, I only take a video for it:

BTW, my KiCAD version is:
Application: KiCad PCB Editor x64 on x64

Version: 7.0.1, release build

Libraries:
wxWidgets 3.2.2
FreeType 2.12.1
HarfBuzz 5.0.1
FontConfig 2.14.1
libcurl/7.83.1-DEV Schannel zlib/1.2.13

Platform: Windows 11 (build 22621), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
Date: Mar 11 2023 03:41:46
wxWidgets: 3.2.2 (wchar_t,wx containers)
Boost: 1.80.0
OCC: 7.6.2
Curl: 7.83.1-DEV
ngspice: 39
Compiler: Visual C++ 1934 without C++ ABI

Build settings:
KICAD_SPICE=ON

I just update KiCAD to 7.0.1 today, and I haven’t met this problem in previous version of KiCAD.

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I found that I can only place a via on a track which is in vertical direction or in horizental direction

yes, that can be reproduced (with v7 and v799), that looks really like a bug. Let’s see if we get more confirmation. So my first answer could be false.

The workaround (use Shift+CTRL-key during via-placement) still works, albeit the via than doesn’t breaks the track nicely.

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I can confirm I can also only place vias on vertical and horizontal tracks.

Application: KiCad x64 on x64

Version: 7.0.1, release build

Libraries:
wxWidgets 3.2.2
FreeType 2.12.1
HarfBuzz 5.0.1
FontConfig 2.14.1
libcurl/7.83.1-DEV Schannel zlib/1.2.13

Platform: Windows 10 (build 19044), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
Date: Mar 11 2023 03:41:46
wxWidgets: 3.2.2 (wchar_t,wx containers)
Boost: 1.80.0
OCC: 7.6.2
Curl: 7.83.1-DEV
ngspice: 39
Compiler: Visual C++ 1934 without C++ ABI

Build settings:
KICAD_SPICE=ON

Other workaround, that may work (at least for me):

  1. Place the mouse on the track you want to place the via on but not on the exact same location.
  2. Press X to start placing a track.
  3. Press V
  4. move the mouse where you want to place the via.
  5. Place the via (this works for me, while placing it freely does not work in 7.99).

KiCad removes the additional track of step 4 automatically, so do not worry about placing a (unwanted) track this way.

So I have opened a gitlab-issue for this bug: via placing not possible on 45° tracks (#14293) · Issues · KiCad / KiCad Source Code / kicad · GitLab

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