I'm sure there are ways it can be sped up, although most of it is magic's converting rectangles into its corner-stitched tile plane database. It's not just reading and storing rectangles. It just occurred to me, though, that since it writes out rectangles that are already in the "maximum horizontal stripes" format, following a known search order, there's probably a modified method that could just create the plane in a single pass. I'll have to give that some thought. There was another solution that I was thinking about recently, noting that it's digital layouts that are the worst-case scenario, and the reason is that every other metal layer is horizontally oriented which is a worst-case for the database generation. Those metal layers take about 10 times longer to read in than the vertically-oriented ones. The idea would be to use a "maximum vertical stripes" format for horizontally oriented route layers. But that looked like a huge task to implement, so I've mostly abandoned that idea.