Is it any chance that Kicad support embedded components?
If yes, how to do that?
I want an 8 layer PCB with embedded discrete 02 (inch) caps and resistors. How large do need to design the “pads” for the components? How close can place vias to those pads? For other areas of the PCB, I need minimum 0.005 trace width and 0.005 copper spacing. How do I get the design rules?
Maybe you can create an ad-hoc solution by enabling more layers in KiCad, and drawing zones on some of these internal layers, and then use these zones as a template for custom milling.
Another limitation is that SMT pads are only placed on the outer layers of the PCB in KiCad. There already is a feature request on Gitlab for SMT footprints on internal layers. This is also useful for “Ridgid/Flex” PCB’s where not all layers span the complete PCB. But it is not supported at the moment.
You can hack into the PCB files and (either manually or scripted) modifiy the layers for certain pads, but I have never done this and don’t know how far you can get with this.