blueprint tools
City plansLayoutsGuideBlueprint Differential
Compare two settlement blueprint exports and pull out just the objects that differ. Want only a few pieces of a big design? In-game, scrap the pieces you want to keep and export again — then drop the full export in Original, the scrapped one in Changed, and Removed hands you back exactly the pieces you kept.
Objects in the original that are gone from the changed export — the pieces you scrapped away. This is usually what you want.