OSH Park Docs
Sprint-Layout is a PCB design tool.
Rename the Files
Subtractive Polygon Planes Extending Beyond Board Outline
Sprint-Layout 6 automatically puts one large polygon plane all over the board on the copper layer, and then adds another polygon that removes copper from the parts where you don’t want it. These are called additive and subtractive polygons.
The problem is that we trim away anything that extends 40mil beyond the smallest rectangle that encompasses your design, and we end up trimming away the subtractive polygon so you get copper everywhere you didn’t expect it.
You can detect the issue in the preview images by looking at whether the Board Top and Board Bottom previews extend past the edge of the board outline further than you’d think they should. That indicates the presence of a subtractive polygon.
We can correct the issue on the gerbers, so the fix for now is to send us any Sprint-Layout files to firstname.lastname@example.org so we can confirm the issue and manually adjust the design before you order.
Also, make sure you turn off the “Pilot Holes” or “Pad Via Holes” option, since that will make the board unusable.