I am reading the book “Kicad Like a Pro, 2nd”. Inside the book is an example ( Project 3 ) where to use freerouter with a 4 layer board. The layout has two net classes. The default and the second called power which includes Vcc and GNDPWER. When I select the power type for layer b.cu then this layer is not displayed in Freerouter anymore. What is the reason for this?
You don’t mention which version of Kicad you are using. The ‘freerouter’ autorouter is an external application and not directly linked to KiCad any longer and not directly supported. I am not certain but I thought that it only ever routed two layers anyway - have you checked that you are trying to autoroute the correct pair of layers?
If I use this version of freerouter (https://freerouting.mihosoft.eu/) then 4 layers will be routed. But the dedictated layer for power is still not possible.
I made FreeRouter route a something like 10 layers.
Go into Utilities -> Parameter -> Autoroute
Then enable all the layers you would like to use
I noticed it use the top and bottom layers first so just to test its function i placed a keepout area on both top and bottom layer to force the router to use other layers.
I’m all new to KiCad and FreeRouter so i might have done something entirely diffrent to make it work.