KiCad hangs when Fill All Zones is used in certain circumstance.

Description

When manually placing vias either one at a time or using the "create array" feature for via fencing, KiCad subsequently hangs when you try to Fill All Zones or to build each zone separately. This seems to be linked to how many vias are placed.

However, when using a plugin such as the "RF Tools", KiCad works as expected, rebuilding the zones properly.

Steps to reproduce

  1. Create any project with an impedance controlled track. Your PCB must have zones on a copper layer.
  2. Lay the impedance controlled track. Then place via fencing along that track either manually or using the "create array" feature.
  3. Place several vias for fencing (usually more than 20) along that track.
  4. Attempt to rebuild zones.

This has been tested in both Windows 11, and Debian Linux.

Please see issue 66215 on the forum:

forum.kicad.info/t/crashing-on-zone-fills/66215

The following project is attached for clarity.

ICP2_Canceller_Simplified.zip

kicad_fill_fail_simplified.jpg

KiCad Version 

Application: KiCad x64 on x64

Version: 9.0.7, release build

Libraries:
	wxWidgets 3.2.8
	FreeType 2.13.3
	HarfBuzz 12.2.0
	FontConfig 2.15.0
	libcurl/8.17.0-DEV Schannel zlib/1.3.1

Platform: Windows 11 (build 26200), 64-bit edition, 64 bit, Little endian, wxMSW
OpenGL: Intel, Intel(R) Arc(TM) Graphics, 4.6.0 - Build 32.0.101.6314

Build Info:
	Date: Jan  2 2026 01:00:49
	wxWidgets: 3.2.8 (wchar_t,wx containers)
	Boost: 1.89.0
	OCC: 7.9.2
	Curl: 8.17.0-DEV
	ngspice: 45.2
	Compiler: Visual C++ 1944 without C++ ABI
	KICAD_IPC_API=ON

Locale: 
	Lang: en_GB
	Enc: UTF-8
	Num: 1,234.5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)
Application: KiCad x86_64 on x86_64

Version: 9.0.7, release build

Libraries:
	wxWidgets 3.2.9
	FreeType 2.14.1
	HarfBuzz 11.4.5
	FontConfig 2.17.1
	libcurl/8.15.0 OpenSSL/3.5.4 zlib/1.3.1 zstd/1.5.7 libidn2/2.3.8 libpsl/0.21.5 nghttp2/1.66.0

Platform: Freedesktop SDK 25.08 (Flatpak runtime), 64 bit, Little endian, wxGTK, X11, pop, x11

Build Info:
	Date: Nov 11 2011 11:11:11
	wxWidgets: 3.2.9 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.90.0
	OCC: 7.9.3
	Curl: 8.15.0
	ngspice: 45.2
	Compiler: GCC 15.2.0 with C++ ABI 1020
	KICAD_IPC_API=ON

Locale: 
	Lang: en_GB
	Enc: UTF-8
	Num: 1,234.5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)
Edited by Armon James