In Eagle I often prefer to route some wires myself (power, xtal, UBS, etc), and leave the rest to the autorouter. When I am not pleased with the result I route some more myself, and let the autorouter have another try.
My problem is undoing the work of the autorouter, without undoing my own work. The basic way to do this is simply not saving the autoroutered version, and then loading the board again. But once I make the mistake of saving the autorouted version (and purging the backups) I still want to be able to go back to the pre-autorouted version.
One attempt to do this is to identify all autorouted wires in an ULP and create the command string to RIPUP these segments. I can arrange for the ULP to identify the autorouted wires, for instance by giving them a different width. But the RIPUP command seems to ripup the selected wire segment AND AJACENT SEGMENTS. So far I have not found a command that rips just the selected wire segment.
I tried the opposite approach: in an ULP, gather all wire segments I want to keep, do a full ripup, and then restore the wires segments (using the ROUTE command). No succes, the segments must be in a specific order for the route commands (not the order in which the ULP finds them 
), the via's must be made first, and some more problems.
So I guess I have two questions: - How do you combine hand-routing and auto-routing in an iterative (trial-and-error) way? - Is there a way (probably using ULP and commands) to ripup a subset of wire segments?
