November 3, 2026

KiCAD - polygon pour

I have been urged to use this on my board. I was going to avoid it, thinking it was only required for RF designs or really high speed designs. There is another reason, namely that it avoids the need to etch away all of the copper, consuming etchant and adding waste to the environment.

My layout is finished, and I generate a backup before trying out this polygon pour business.

I go back to "board setup" and look to see if there is a clearance specific to filled zones, but there is not.

Notes from the video

I go back to part 2 of the Phil's lab KiCAD 9 video. Around 1:16 is when he does his polygon pour.

On the right is an icon for "draw filled zones" I click on this, then left click to get a menu. This has the clearance value I expected to find in "board setup" and it is set to 0.5mm just as I desired. I can select the layer here and I select only B.Cu I select the net (as GND) and name the zone L2_FILL. I select corner smoothing as fillet and keep thermal relief. I click OK, and then draw around the entire board.

Something went wrong and it did my pour on the front copper. I use Ctrl-Z and then select the zone and use DEL to get rid of it.

I start over, making sure B.Cu is the selected layer when I start. I also double check this layer slection in the zone dialog. This is even worse. I exit KiCAD abandoning changes and try again. This looks good.

The only thing I would change if I did the board over, would be to select different mounting holes that I could connect to ground. But I am not going to tackle that now.

I repeat the fill game with the top layer, calling in L1_FILL. This works out fine without any confusion.

It is pretty amazing how this works.

I finish with a design rules check.

Have any comments? Questions? Drop me a line!

Tom's Electronics pages / tom@mmto.org