Is there a way to add arbitrary additional layers on the board to draw various non-copper features? This would be particularly useful for
- screen printing layers (resistive inks, special dielectrics)
- special masks for gold fingers, etc
- flex stiffeners.
Right now, there isn’t. But since we now have ODB++ (which supports the things you listed) export, there’s guidance how to represent such things.
In terms of UI, I’ve been thinking about extending the existing stackup dialog to support adding custom layers between existing layers. There’ll be some extra work required to fit them in and handle that their layer number doesn’t reflect the position within the stackup. A slight issue I see is that these new layers will have their colors set on a per-board level, so they might not work well across multiple users using different color schemes.
Out of curiosity, what’s your use case for these extra layers?
I think the clearest use case for me would be adding layers on top and bottom to specify the location of stiffeners for flex circuits.
A less common use is to specify special screen printing layers, for example to screen on resistive inks and dielectrics.
To be clear, screen printing for the design of hybrid circuits.