PCB rule system and full list of rule words , and How To?

[glenenglish]

Where is the full list of what can be in the custom rules ?
The documentation does not seem to have all the listed words and rules.
Can someone maybe point me to the source code location to look at it? I could even do some doco…

I have a zone of copper that is GND top and bottom layer
I have two components R1 and R2 and R3 , thru hole parts they have different footprints

I want to have THERMAL RELIEF for pads of designator R3 for bottom layer copper zone but direct connect for top layer copper zone.
I want to have a DIRECT connection for pads of footprint “AXIAL4” for top layer copper ZONE and bottom layer copper zone.

… and the R3 rule to have precedence, so it goes last.

I could not find how to drive the rules to do this ? how to specify designator and footprint to refer to a component for a rule match ???
thanks, glen

[paulvdh]

This folder gets you close:

pcbnew/drc · master · KiCad / KiCad Source Code / kicad · GitLab

I never looked much at KiCad’s source code. Just went to KiCad on gitlab, and chose the most logical sub directory starting from the top of the source tree. The drc_rule.h file has an enum with a list of constraints.

[glenenglish]

thanks
. anyway else have information on this, and how to implement ?

[gkeeth]

The documentation for this is very thorough: PCB Editor | 7.0 | English | Documentation | KiCad

(switch the doc version from 7.0 to nightly if you’re using v8)

Of course, thorough documentation does not mean it’s trivial to write your first rules There are some examples there that might help you get started.

[paulvdh]

Some more examples:
(Including a big fat arrow to the “Syntax Helper” )

Custom Design rules Examples

KiCad has the ability to create custom design rules for DRC that modify how clearances are calculated and applied. The formal documenation for these custom design rules is on: This FAQ article is an attempt / start to collect examples of such rules. A short description on what the goal of the rule is, preferably with a link to a picture already on this forum (just copy a link from the original and post it here. No need to copy the whole picture. This forum software understands). The actual …

[glenenglish]

I dont think Syntax helper is up to date. But that’s something I can go through the code and fix.
I do understand that if I really dont like something or need something, then I can code it… that’s the positive. I’m not really used to working in a big dev group, but I can learn.

[gkeeth]

The syntax help doesn’t have everything (it’s missing a few classes of objects), but what’s there should be accurate. If it’s not, please file a bug.