I have a copper fill all the way to the board edge and I want to pull back the mask to expose the top and bottom copper layers along this edge. I tried creating a fill zone and a keepout which only has zone selected and mask layers where I want the mask to pull back. However, in the 3D view, I still see solder mask in the masked out areas. Picture below (red hatch is copper fill, blue hatch is keepout; the blue hatch ends on the vias).
I checked the gerbers to make sure this isn’t just an artifact and I see the same:
What is the correct way to achieve this outcome? And before you ask, this is not a hard gold edge etc.
If I understand correctly, you want to create a cutout in the soldermask layer to expose the copper underneath?
The soldermask layers are negative layers, meaning that there is soldermask everywhere there is nothing drawn on the layer, and no soldermask anywhere you draw on the layer. So to create a region without soldermask, you can draw a graphic shape (polygon, rectangle, etc) on the soldermask layer in whatever shape you want.
