Modifying an existing NetClass

[gianlucarenzi]

Hello folks!
I am going crazy changing the netclass rules in a finished PCB layout (KiCAD 8).
Originally the project was started using 4 layers PCB, but during the PCB design I switched to a 6 layers PCB. All the differential pairs signals, and tracks were set for impedance controlled width when I was started with the 4 layer PCB. Now the netclasses had changed with the new values (Clearance, Track Width [ for single ended signal ] and Diff Pair DP Width and DP Gap).
I was thinking how to change all the netclass segments and vias to reflect the new values, instead of redraw (manually) all those tracks. The Edit->Set Track and Via Properties seems to NOT WORKING. I was thing to select all NetClass and set the new rules value via a single click.
But it does not work.

Am I wrong on this topic???

Thank you in advance.

Gianluca

[paulvdh]

It looks like a bug.
I tried to open the Track width box and enter a value, but I can not put any number in there.

Application: KiCad Schematic Editor x86_64 on x86_64

Version: 8.0.5-8.0.5-0~ubuntu20.04.1, release build

Libraries:
	wxWidgets 3.2.2
	FreeType 2.10.1
	HarfBuzz 2.6.4
	FontConfig 2.13.1
	libcurl/7.68.0 OpenSSL/1.1.1f zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.2.0) libssh/0.9.3/openssl/zlib nghttp2/1.40.0 librtmp/2.3

Platform: Linux Mint 20.3, 64 bit, Little endian, wxGTK, X11, xfce, x11
OpenGL: AMD, AMD RENOIR (DRM 3.42.0, 5.15.0-119-generic, LLVM 12.0.0), 4.6 (Compatibility Profile) Mesa 21.2.6

Build Info:
	Date: Sep  6 2024 21:35:43
	wxWidgets: 3.2.1 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.71.0
	OCC: 7.6.3
	Curl: 7.68.0
	ngspice: 42
	Compiler: GCC 9.4.0 with C++ ABI 1013

Build settings:

[gianlucarenzi]

In my case the “Set to net class / custom rule values” does not change the PCB either. But it should be great if I can select the NetClass for Diff Pair only, because the DP gap is important too…

[paulvdh]

For me too. I can select the Set to net class / custom rule values radio button, but it has no effect. Can you report this on gitlab (First check if it’s already reported).

As a workaround you can select tracks (either from a single net by hovering and pressing u a few times) or use the selection filter in the lower right corner and then a box select and then press e to edit track properties of all selected tracks.

[gianlucarenzi]

My biggest concern is change the Differential Pairs at one time. Anyway it seems on the DRC Checker if the DP gap changes the Error is not thrown. It looks like something an interval and not a fixed value.