I am trying to create a ring of exposed copper at the edge of a board by creating a shape on the solder mask top, however I can't seem to make an actual ring rather than a big filled plane. I can use z-copy to get the outer edge from my route keepin, but I can't figure out how to use a shape to generate a void (I would love to use z-copy to make the void the same shape as the route keepin, but contracted by 30 mils). Any suggestions, or is there something really obvious that I'm missing here?
I found a way to do this. If you create two unfilled shapes that represent the inner and outer boundaries of the ring (I did this by z-copying the keepin referenced above, once the same and once contracted by 30 mils, and decomposing both resulting line/arc items) compose a shape using these, it creates the ring exactly as I wanted it. I was going to delete this post, but I figured anyone looking for this might want my solution...