During routing, does it use netclass information?

[HarjitSi]

I've attached net class information to all nets. Will the router use that?

[drandyhaas]

Yes — the KiCad plugin reads net class parameters (track width, clearance, via size, via drill) directly from the board.

In the plugin's Basic tab:

1. Check Use net class definitions — track width / clearance / via size / via drill controls become disabled and the per-class values from the board are used instead.
2. Optionally check the separate nets by net class option to organize nets into one tab per class. With both checked, each class's nets are routed with that class's parameters in a single run.

When nets from different classes are routed together, the obstacle map uses the larger clearance for each pairing, so e.g. a Wide (0.4 mm clearance) net routed near Default pads still gets the 0.4 mm gap.

Note that this currently only reads track width, clearance, via size, and via drill from the net class. Diff-pair width/gap from net classes is read but applied separately via the Differential tab. Things like uViaSize, custom rules, and length-matching tolerances from KiCad's netclass definitions are not consumed by the router — those still need to be configured in the plugin GUI.