I'm going to try and explain the issue I'm having with as much detail as humanly possible. Please read all of it so you know what the actual problem is
Back in March, I was working on building a city on an island, online. We'll call that "World A" from here on out. Recently, I decided to start a new world, which we'll call "World B." I want to take that old city and move it into the new world. The solution? Copy the region files from World A, rename them, paste them into World B. Simple, right? Well, it gets crazier.
Both worlds can load in single-player without a hitch. But the item ID's in World A are different from the item ID's in World B. What I mean by this is that an item with an ID number of, say, 410:12 in world A might have the id of 573:6 in world B.
The end result is exactly what you're guessing it is: a door in world A is a sink in world B. Chisel cement in world A is some other mod's block in world B.
Both worlds have the same mods, though most of the mods in World B are updated beyond where they were in world A. Too much of both worlds are built using mods. Probably 80% of each is built using mod items. Getting the ID's to match up is pretty much all I need to do.
Is there a way to uniform the item ID's in both worlds? Is there a tool I can download that would fix the item ID's in both worlds, or a mod with a command or something? I don't want to lose the city (it's quite epic), and the work I've poured into this new world is extensive as well. There has to be a way to keep my city island and move it into the new world, without manually going through and changing the block ID's of every single mod block and item, right?
Do you know of any ways to do that? I could try Buildcraft bots or something, but it's a whole city so that would take a while. Are block IDs saved in the region files themselves? Is their some mod that sorts out IDs by name?