After finishing my project I used ViewMate to verify the gerber files and upon opening the files it complains about self-intersecting polygons. For example, with BLDC_controller-F.Cu.gtl it points to the location illustrated below:
Copper Zone properties:
Observer that the figure above is made using “show outlines of filled areas only in zones” but those extra intersections disappear if I choose “Do not show filled areas in zones”:
I also decoded the kicad generated gerber files BLDC_controller-F.Cu.gtl (197.2 KB)
with speadsheet program and it seems that the kicad is indeed generating self-intersecting polygons or at least polygons that are adjacent to each other sharing the edge points with six digit after the decimal separator.
I found some old thread that claims that this should not be an issue when kicad uses metric units with 6 digit mantissa in gerber plotting.
Is this a bug in kicad or bug in Pentalogic ViewMate? Should I create a bug report or is it just me not knowing how to use kicad?
Complete project can be found here (this post refers to commit 76a24469dfe859fd4511a63ceba10a6f6e923f0a):
I am using KiCad 4.0.6 under Linux Mint 18 (ubuntu 16.04) but I am able to reproduce it also with kicad 4.0.4 and 4.0.6 under Windows 7.