A well known and pricey PCB suite has the option “select used layers”, but in the ‘presets’ section of KiCad, such an option is not there. I can select copper, all, back, front…
It may be I can create a preset or macro to do this, but I don’t have enough knowledge of the steps required.
Such a filter would enable me to choose ‘select all used layers’, upon which I could immediately see (for example) that internal copper 3 is not used, hence I could use that layer freely for routing, or zone it GND, or delete it (and it’s pair) from the stackup entirely, reducing manufacturing cost.
I had to re-read your post trice to understand you are already familiar with the Presets in the lower right corner of the PCB Editor:
My next question is, hen do you consider a layer “used”. Is this only for copper, or also for other layers? The number of copper layers is a very mayor factor in the price of a PCB, and this is usually not decided “on the fly”. For KiCad it is set in PCB Editor / File / Board Setup / Board Stackup / Physical Stackup. Just above that, there is Board Editor Layers and you can set custom names for layers and decide whether the Appearance Manager shows them at all.
I guess you wish some “automatic feature” for this. But KiCad does not guess which layers you want to use. You have to set them manually, but normally it’s only once per project and the current system seems good enough to me.
