I've detailed this in the past, but to summarize: > -You would need to have some way for the program to in advance how much > angle (arc) you wanted to cover.
It's automatic. The straight parts are always tangents to the curves around obstacles. See the png I posted. > -You can probably pack more traces in when routing manually only at a > n*45 degree angle. This optimization would always be the last thing you did, and it would be iterative - it would keep fiddling with traces until they were *all* as short and smooth as possible. At least, the ones you wanted fiddled with. > -Autorouting and DRC calculations would probably get more messy. They're already messy. The user can create arbitrary traces already.
