snarflemike wrote:I'm using Eagle right now, but I'm sure my question is not Eagle-specific. When using an autorouter, what are the guidelines/tradeoffs in selecting a value for the routing grid?
If you have a low density board (mainly DIPs), then a 25-mil grid may work. Otherwise, I'd go for a 10-mil grid, or possibly a 5-mil grid. Basically, try different grid and see what works best for your board. I've noticed that EAGLE's auto-router (AR) leaves a bunch of wiggly lines when the grid is too small. It looks like it "changes its mind" quite a bit with small grid settings. I've gotten tired of cleaning up after EAGLE's AR, so I rarely use it anymore. If nothing else, running EAGLE's AR will give you some ideas of how to manually run traces.
I think that most people "know" that EAGLE's AR is lousy. There is an on-line AR that works with EAGLE and is much better, but I can't remember the URL (sorry). I've played with a demo of Pulsonix and was really impressed, especially with its AR. I don't have the money for Pulsonix ($3K - $5K) or enough freelance work to justify buying it, so I'm sticking with EAGLE for now.