Ground-pour behaves unexpected

I’m trying to simulate a hatched ground-plane area, a feature that KiCAD doesn’t support. I want it because my laser-printer doesn’t like big black blocks. So I made a diagonal keepout area that doesn’t touch the edges of the board, saved it and opened the resulting pcb file in Gedit. I figured I could replicate the keepout area 60 times, so I instructed my spreadsheet to calculate coordinates for 65 copies.
The good news : it works !
Of course some area’s were not covered with copper, but I figured I could easily correct this with some traces.
The bad news was that KiCAD ignores a trace carrying ground-potential that is running through the area to be filled. It will only recognise the endpoint of the trace. So you have to manualy draw some sort of christmas-tree.

I’ve been using KiCAD only for a few weeks, so maybe i’m just missing something, but as far as Google can tell me there is no better solution.
Or is there ?

1 Like

One other thing I tried was to use Inkscape to convert the ground-area to a hatched pattern instead of an color. It failed because Inkscape ran into some kind of memory-leak and then crashed.

Can you post a screenshot of what you expect plus maybe one of what you currently have. (Might be easier for us to offer advice.)

This is true.

Hmm, perhaps a module that has a cross-hatch pattern, you could duplicate that as needed. Might have to fill in with tracks.

I’m wondering how to use a script. Possibly if you used a special net name attached to a zone, a script could fill the zone with a pattern.

Most of the time, my expectations only exist in my mind and it is hard to produce a screenshot. But this one I finished, it’s just that in the future I would like to spend less time :slight_smile:

What’s the point in having a gnd fill like this?
There is only one direction where there is a short path for currents on gnd. All other paths are incredible long. (need to flow to the edge of the board and back)
You could achieve the same result simply by placing traces.

The reason for a gnd planes is to ensure unhindered current return paths. (low impedance) without needing to worry about drawing them by hand.
Any interrupted plane does a bad job at this.

A plane that is chopped up like this might be even worse than connecting the gnd by hand. At least overlay a second cross hatch rotaded by 90 degree to the current cross hatch to have a chance of having short connections. (still not ideal but might be better than what you have now.)

This is not a realistic example, but might help to reduce the fill %. I used a 10x10mm module, that could be changed to any size or pattern of course.

Edit: I would add a SMD pad to allow connection to a net.

1 Like

Yes it is very ugly, but it’s supposed to be a prototype for a much smaller board. This one should be home-made.

The point is to keep the laser-printer happy. I will fill the gaps between the tracks with a fat felt-pen after I transferred the board via the toner-transfer method.
As I mentioned before, this is a prototype. I learn. I sent in a board for production only to find it had 5 errors. This handmade prototype will save that cost + 3 weeks.

If your laser printer is unhappy with that maybe you could look into having it printed at something like a Kinko’s or Office Max or some small mom/pop print shop. I’ve heard some folks say they get better quality transparencies that way anyhow because those places have higher DPI machines and make ‘blacker’ copies.


Also less danger in marking the wrong area with the marker pen (or forgetting to mark some small area that would have been important.)

And if you think about how many hours you probably use for doing it on a crappy printer you might as well buy a better one and have more time for stuff that is actually fun to do.

If @JC_D really wants to use their current printer, it would probably be easier to have only the zone outline printed and color the complete zone by hand then to color the rest of such a stripey area.

I can not figure out where the outline of this zone really is. At least from the screenshot i can not tell, maybe it is easier if one only sees the one copper layer. But a 1:1 printout will be smaller than what is currently on my screen.

I provided an example of creating a cross hatched polygon in pcb-rnd in the following discussion thread, which can then be exported in kicad format for use in pcbnew:

There is also a related blog post:

We had to implement polygon cross hatching to allow export of non rectangular fills when saving in legacy Protel Autotrax/Easytrax file formats, but the :PolyHatch(interactive) routine can be used on any polygon in a layout.

IIRC, the PolyHatch() command is in svn head currently, but I believe the next pcb-rnd release scheduled for release in the next week or so will include it by default, so that debian/Ubuntu should have the new package which includes it shortly by default.

Two cautionary notes:

  1. kicad does not support arcs on copper, so any arcs on copper created in pcb-rnd will not export nicely to copper layers at present (interpolation with segments is planned)

  2. if you have vias in the polygon zone, their connectivity will not map properly during the round trip to and from pcb-new. In Eagle, gEDA PCB and pcb-rnd a polygon is just a polygon, not an “administrative zone” dictating connectivity of vias within it.

Enjoy responsibly,



The printer and transparency combination can make a surprising difference. We use an Epson Artisan (1430?) printer (wide format) with Pictorico Pro Ultra Premium OHP Transparency Film.

Has excellent consistency and dark clean smooth blacks without splotches.

Wouldn’t it be easier to OVERLAY the filled zone with rectangular KEEPOUT zones via the array function?

To be honest, I now expect someone to write a python script that does this :hugging:

1 Like

It is quite large actually, ( 10 x 16 cm ) because I have no cutter and it’s a standard size. I don’t use transparencies, it’s transferred directly from the paper to the copper. It took a lot of experiments to get the method right. You can’t do this in a printshop, because fast printers have too high temperature fusers for coated paper.
I have more time than money. My printer is a HP CP2025. I think it is not worse than any other laserprinter. They just don’t like big black surfaces. It looks OK at first sight, but you can see through it. Also smaller features transfer a lot easier than large ones.