Extraneous traces on 3d view & gerber, but not on pcbnew

I sent my first set of files to an outside fab house to get some proto boards made, and after checking the gerber files with gerber view, it appears that there are 5 or so vertical lines going through the back copper layer that don’t appear in pcbnew.

They DO appear in the 3d viewer…This happens only on two of my boards(one was started from a copy of another), but not on some other boards I’ve checked.

The lines appear to not be part of the layout, because if I move the layout around in pcbnew, the extraneous vertical lines don’t move. Using this as a workaround, I sent another set of gerbers to the fab house with the lines outside the edge cut layer, so that SHOULD be OK.

Since this was my first manufactured pcb, I was unaware that it was a problem. The homemade pcbs I did for the same design didn’t have any extraneous lines.

Anyone have any ideas what the hell is going on? I’m using stable release v4.04 on windows10.

Have you tried a 3rd party Gerber viewer like gerbv for Geda

It may help if you posted a screenshot of the Gerber display, and one from PCBNew showing approximately the same region.

If you have not yet heard the admonition, LISTEN CAREFULLY NOW:
ANY time you send a Gerber file to a fab house, review it with a Gerber viewer first!

I have never encountered anything like this, and I’m certain that if it was truly a bug in KiCAD, it would have been discovered, analyzed and reported by now. (I think stable version 4.0.4 is about 4 months old now.) The fact that you see the same defect in both the Gerber viewer and the 3D viewer supports the idea that the lines are truly there, not just an obscure artifact manufactured by a video driver or graphics card. With that in mind it seems that it should be visible in PCBNew.

The following comments are WAG’s on my part.

Is your “Edge.Cuts” layer clean? If you had stray lines on Edge.Cuts, they will be plotted on copper layers when you generate Gerbers, unless you tell KiCAD otherwise in the “Plot” dialog.

A similar comment can be made about the “frame” (or “format border” ) of the worksheet, though this is less likely.

Did you inadvertently move a trace or graphic element when you moved a group of components?

Did you inadvertently start to draw a line or trace, then realize you had not selected the active layer you wanted? (Especially if the active layer was not visible during the drawing. After years of using EDA tools, I still occasionally start to place a line or trace, only to discover it’s not going onto the layer I want it on.)


I prefer “gerbv” to the viewer in KiCAD.


The advantage gerbv has is that it doesn’t share code with Pcbnew.
There is a remote possibility that Pcbnew might create faulty Gerber plots and due to a corresponding bug affecting GerbView not reveal the error.

I second the advice from @dchisholm “ANY time you send a Gerber file to a fab house, review it with a Gerber viewer first!”. Mistakes are expensive and waste time

Do you use a zone fill?
Is it one single zone or several pieces?

But yeah, screenshot would be nice or even the project if you are able to do that.

And in case you want more options regarding gerber checking:

+1 for GCPrevue which is a standard free viewer of a high end commercial product

The only gerber issue I know of relates to arcs, this occurs due to some old buggy software cheap boards houses use.

If you can post a sample board file that would help a lot, otherwise we can only guess. If there is a reproducible issue, it would benefit the KiCad project if information can be provided to enable a fix.

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February 3

The only gerber issue I know of relates to arcs, this occurs due to
some old buggy software cheap boards houses use.

If you can post a sample board file that would help a lot, otherwise
we can only guess. If there is a reproducible issue, it would benefit
the KiCad project if information can be provided to enable a fix.

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OK, what files do you need for me to post?

Here’s a view of gerbv:

Here’s a view of pcbnew:

Here’s a view of the 3-d viewer:


Hopefully these shots will show the issue to you.

Looks like the screen captures didn’t post…what’s the preferred way to post screen images?

I can see your screenshots. (In the last post)
But some of them are posted more than once.

I can’t see the screen shots myself…any idea how to make them accessible?

Dop you see the issues with the vertical traces that aren’t on the layout, but are on the gerber?

I see lines on the Gerber and on the 3d. Interesting they are not in the same place

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Yes, we see the screen shots and we see the lines. I would suspect the problem is in the PCB file. PCBNew doesn’t render it on the screen for some reason but does try to plot it. The best way to find would be to examine the file with a text editor. One possible way to find it would be to make a copy of the PCB file and the delete the PCB from the copy. If the lines are still there then examine the file to see what is causing it then you know what to look for in the original file.

Make sure you have a backup before you go editing the original file.

Ignore that they’re not in the same place, because I had to recreate the pcbnew view, as I moved the image away from the junk lines so I could send something useful to me fab house…

I then ‘recreated’ the image more or less back to the original, but not 100% in the same location.

On the image I sent to the fab house, the lines are still there, but outside the edge cut, so they should be usable…

Can you see images in other posts?
If not maybe your browser blocks them.
If yes try restarting your browser.
You can also try looking at your post without being logged in.

By the way can you see a link that says uploading at the bottom of your post?

Firefox isn’t showing the screen shots, but IE does…

I deleted the pcb file, and the view shows obvious crap…I deleted everything, and created a project from scratch, and the view (and I assume the gerbers) show a blank screen, as I would expect.

So, some file(not the pcb) is causing the issue…I have no idea how to find or correct the issue.

Is there an code that will check a project for obvious garbage???

What were you viewing if you deleted the PCB file? I meant for you to select the PCB and all of it’s footprints and delete them using PCBNew. Or you could post a link to your files for someone else to download and look at.

I am guessing that it is a bad footprint. A kicad_pcb file with the problem would help.