How to Copy Gerbers with Curved Tracks

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Hello, I have a Gerber for a public RF design done by TI. In one of the copper layers, there is a layout section of a millimeter-wave antenna array that has been already been tested and I wish to copy it as is to my design since it has been validated. The issue is, it contains curved tracks like many RF designs and when I export it to a PCBnew file, the tracks lose their curviness and become segmented.

I thought to export the gerber to a DXF file and then import it as a graphic layer to manually create the tracks but the scale and many other details were lost in the process. Is there a better way to do this? I am relatively new to KiCAD so maybe there is a better way that I don’t know about. I attached the copper layer in question and the curved tracks are in the top-left corner. Thx!

PROC073D.GTL (348.7 KB)

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KiCad V5.1.x does not have real support for curved tracks.
The best you can do in V5.1.x is probably to draw arcs on a graphical layer, and then edit them and move them to copper.

I tried to export it in KiCad-nightly V5.99 which promptly resulted in a segmentation fault, which I reported:

Is it correct that you used another (not KiCad related) Gerber viewer to make a .dxf ?

I also did an export with Gerbview V5.1.9 and it also appears buggy.
The export does work, so you can use the exported stuff as a guide to draw over it in KiCad.
There is a dialog “missing” during the export. There should be a dialog to ask which gerber layer goes where in the PCB, But I don’t see it in V5.1.9.

But still.
If you use Gerbview to directly export it to a PCB, there are at least no scaling errors, and as a bonus you also get all the via’s. For editing, you can (temporarily) set Pcbnew to a 4 layer PCB and put the imported copper on an internal layer. And then decide whether to re-use parts of the imported stuff, or draw over it. How close does length matching have to be here?

The Export to Pcbnew results into several overlapping zones and tracks. I have not put much effort into sorting out what those mean.

[Edit] Just got a mail that a fix was commited. That’s 34 minutes from a bug report to a commited fix. So with a bit of luck you can try V5.99 for this after the next nightly is available.

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It doesn’t do any good job, here’s the file exported to pcb with 5.99: noname.kicad_pcb (1.4 MB)

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I mistakenly implied that exporting with Gerbview V5.99 would result in better exports.

Duh…
Support for curved tracks (and changing their curves) is slowly coming into the nightlies, and Gerbview exporting them as curves would be a separate issue.
But at least you can experiment more with drawing curved tracks in V5.99 (Even if you exported with Gerbview V5.1.x, and then open it in KiCad V5.99)

Curved tracks is an issue being currently worked on, so support is partial. To get an idea of it’s current state, do something like:

https://forum.kicad.info/search?q=curved%20tracks%20order%3Alatest

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Thanks, Paul for the support. How do I download V5.99? I tried searching for it online and I couldn’t find a useful link.

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V5.99 is the “nightly” build. How to get it depends on the OS you’re using. The nightly version can be installed (and run) at the same time as the stable version.

For me it was as simple as following the instructions on:

sudo add-apt-repository --yes ppa:kicad/kicad-dev-nightly
sudo apt update
sudo apt install kicad-nightly

But beware the dragons when working with nightly builds.

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Okay, thanks. That helps. I am using Ubuntu and I found the instructions here:

https://kicad.org/download/ubuntu/

It is downloading and hoping it makes things easier. Thx!

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Nobody is waiting for a quick response here.
It’s more useful to report back what you did (and possible problems you encountered and how you fixed it).

Forums like this are used in (at least) 2 different way’s.

  1. By people asking questions and responding (Such as you & me here)
  2. By people searching and reading existing threads for similar problems to their own.
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The patch is working.

The gitlab issue has nothing to do with the curved tracks. It only was about a very small bug that caused Gerbview to segfault on comments in gerber files.

As I wrote before, support for arcs in tracks is still in it’s infancy state in KiCad. In KiCad-nightly V5.99 you can directly draw arcs on copper. For more about these new (to KiCad) features view for example:

Note that that post is dated 2021-01-24, only 4 days old.

Back exporting curved tracks from Gerbview to Pcbnew is another subject altogether. This issue has been posted on Gitlab 8 months ago:

That issue is labeled as both “Feature request” and “Wishlist”, and does not have a high priority. Currently the focus on KiCad development is on getting V5.99 bug free so it can be released as rc V6.0. This issue may get more attention after V6 is released officially and the bugs are ironed out.

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Seems to be installing on Ubuntu Mate at this very moment.

Thanks!

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Don’t thank me. I just copied that text from the KiCad website.

So thank the website maintainers, and also the people who tought up this whole package management thing for Linux which lets you install (and update) programs with just a few lines of text in a terminal.

And of course, put a bit of love in the direction of the people who build and maintain the packages for KiCad themselves.

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Probably should have included this quote:

I knew this was the case for Win7, at the moment, but I did not know if it was the same for Linux.

Also, my downloads are typically throttled near the end of the billing cycle and very slow. I see that the download is also downloading ~380MB of packages3d. I know that when I downloaded KiCad V5.1.5 I used the Synaptic package manager and avoided downloading any of the 3D_models. I played “sneaker net” (where one takes a thumb drive from one machine to the other … and copied the 3D_models from my Win7 machine and then walked the thumb drive over to my Ubuntu Mate machine) to get the 3D_models without having to re-download them.

Any idea if there is a way to download the nightly and avoid re-downloading the 3D_models?

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It’s Linux, so (almost) everything is possible

“kicad-nightly” is a combined thing (I think called “meta package” or similar).

If you do a search for it, you can see that it consists of several sub packages:

paul@medion:~$ apt search kicad-nightly
i   kicad-nightly                                   - Electronic schematic and PCB design software              
p   kicad-nightly-dbg                               - Debug symbols for kicad                                   
i A kicad-nightly-demos                             - Common files used by kicad                                
i   kicad-nightly-footprints                        - Kicad footprints (modules)                                
i   kicad-nightly-libraries                         - meta-package for dep to all KiCad libraries (symbols, foot
i   kicad-nightly-packages3d                        - Kicad packages3d (3d models for footprints)               
i   kicad-nightly-symbols                           - Kicad symbols (schematic)                                 
i   kicad-nightly-templates                         - Kicad templates

Apt is a user friendly frontend for dpkg (Debian Packaging) to do the most common tasks. If you delve a bit deeper there are commands for downloading separate packages without installing, installing from certain locations, preventing packages from being updated and lots of other things, but I do not use those much myself.

A quick search:
https://html.duckduckgo.com/html?q=linux+prevent+a+package+from+updating
suggests to use apt-mark to change the status of an package, or use aptitude if you like a GUI.

It’s been a long time since I bothered about download speed or size. In the old day’s I sometimes started them just before going to bed, and it was always finished the next morning.

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