Holes and Islands - Processor Issues
One of our primary customers for this product is having some difficulties with the use of re-entrant polygons in the output and would like Artwork to provide some optional treatment. This section discusses the current behavior and what those options might be.
Our client provides a set of design rules. It appears that our approach using re-entrant polygons clearly violates the rules. Here is a summary of the rules:
Split Polygons with Holes
Avoid self-intersecting or nearly self intersecting polygons
However further in the recommendations, our client (the manufacturer of the image writer) recommends that for Gerber input the designer take advantage of what Artwork calls "paint and scratch" layers. In 274X parlance, this is LPD (layer polarity dark) and LPC (layer polarity clear).
They provide an example: