Strange behavior of the copper fill tool


I have designed a board with a small switching power supply, doing the placement of components and adding the 3D models when not already available. However, I want to fill some areas of the PCB with copper, following the layout recommendations found in the switching power supply IC datasheet. I successfully succeeded in adding a ground plane on the back side of the board. However, when I try to fill ground areas on the front side, a strange phenomenon occurs: when I try to create and fill separate areas, the filling tool fills some of them while refusing to fill others, depending on which of those ones I create first. The same thing happens I draw a big area, encompassing all the regions I am interested to fill: it does not fill all the areas which I succeed in filling separately. What should I try? Thank you all in advance.

My system infos are reported below
KiCAD version:4.0.7, release build
wxWidgets 3.02 Unicode and Boost 1.57.0
My platform: Mac OSX (Darwin 17.6x86_64), 64 bit


Uploading a screen shot would really help.


It is likely that you need to adjust the zone priorities. The ‘Fill’ dialogue allows you to set a ‘Zone Priority Level’ for each zone. You need to set your innermost fills to a higher level (numerically) than the outer ones. So for example, set the inner to 2, any immediate surrounding zone to 1 and the backplane to 0.

(Recent nightly)


Thanks John, I’ll try this. And also I’ll post some of the pictures, as Sprig asked.


If nothing is connected to that zone then it also wont fill. That is a problem i sometimes stumble upon.


John, it seem it was a problem of priority setting. I succeeded in filling the zones inside the board by rising their priority to 1 or 2. I also found that there were non connected zones as Make-ing pointed out. Thanks


By checking carefully the connection of the zone, I found a couple of them that non connected to anything. Thanks