I have recently finished converting Europa Barbarorum to use -mod: and there were only a couple of points that I felt needed addition to this thread:

Entries in *.txt files that reference files for Rome but do not include a directory structure beforehand cannot be told to given a different directory structure - it is inbuilt into the *.txt file.

For example in descr_aerial_map_ground_types.txt has this entry

Code:
cultivated_low		temperate_grassland_farm.tga	arctic.tga
as you can see it does not reference any folder beforehand and so adding eb/ as a prefix, to reference that file in a different folder, did not work

Code:
cultivated_low		eb/temperate_grassland_farm.tga	    eb/arctic.tga
The only alternative was to rename the files, I gave the updated files the 'eb_' prefix, so that they do not over-write the vanilla files. I then put these 'eb_' prefixed files in the appropriate folder (in this case data/terrain/aerial_map/ground_types/) and changed the entries appropriately.

Code:
cultivated_low		eb_temperate_grassland_farm.tga	    eb_arctic.tga
.

Also, as far as I can tell, you cannot add custom loading bars to your mod if you wish to use the command '-mod:' without over-writing vanilla files. Does anyone have any hints as to a solution for this. It is not referenced in a *.txt file as far as I can tell, but it will not show the custom loading bar!

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