> > Areas the autorouter shouldn't put traces through. > > What's the reason for such areas?
Mounting brackets, component contact, EMI, isolation, etc. For example, on my furnace controller I didn't want the logic lines getting too close to the power lines, so I manually drew big fat tracks between them before routing. If I had keep outs, I could have drawn those tracks on the keep outs and not had to go back and delete them later.
