Well hello. Since Yellowrose would like me to explain how to combine z2f files, we thought it was a good idea to post it in here, so if anyone needed help, they could find it here.
So you want to know how to combine z2f files.
Well first you unzip the z2f files (just unzip in a folder for each file). Combining the same type of objects or animals is easier than if you want to combine say a path and an animal.
I think it's best to explain it by example, so here goes.
Combining 2 paths from 2 z2f files
You have a file called catspath1 and catspath2. Unzip those to say folders called path1 and path2.
As you want to combine you can just ad the files from path2 to the folder path1.
Open path2/entities/ai and copy these files (in this case there are two files), then open path1/entities/ai and paste then here.
Now open path2/entities/ and copy the folder catspath2 and paste it in path1/entities/.
Now this takes care of the entities folder, so go open path2/lang/1033 and copy this files and paste in path1/lang/1033.
The same goes for path2/ui/zoopedia/entries. Copy the file in here and paste it in path1/ui/zoopedia/entries.
Now you are done and have combined those to files, so there in the entities folder now are two folders catspath1 and catspath2. And in alle the other folders there are files from both z2f file. Now you just have to zip it up like you are used to.
Combining to different kind of object files
Like in the previous example you need to have the same structure for each file. So when animals have folders: ai, entities, lang,ui it must have that in the new file too. So they easiest thing to do, is make the z2f that has the most files the base (our path1 folder in the previous example). The just open the folders that the next z2f file has and copy like before, keeping in mind that if you path has some new folders they must be copied and maintain the structure.
So if you have a path and some foliage the final one will look like this (in the entities folder)
entities/objects/scenery/paths/name of the path and have the folder entities/objects/foliage/name of the foliage.
Ok I don't know if this was more confusing than helpful, but just post away and maybe I can explain more. It's easier when it's examples than to explain it in general. But the new folder/z2f file must contain all the folder from both (or if you are combining more) files, and keep their original structure.