on the items it should do it for an existing building if you follow Alpaca's tut and delete the existing items.db file.
Things to watch - it only actually makes the conversions in sequence with when it gives you the error message that its missing XXX and you click through - so you'll want to move any existing building you're trying to remake to the top of the items.txt file!
We did it for walls from mod folder so you have entries like
moved to the top of the file, in our case path is for working from bi mod-foldertype roman_town_wall_straight
lod
max_distance 4000.0
model_rigid ../../bi/eod2/data/models_building/roman_town_wall_straight.cas
for the generation if you tell it to look for your new cas in a mod-folder or differently named folder that should sort out any confusion with it trying to refer to RTW packs for the model.
If you let it run through the items.txt list till it gets to the existing models, a lot of them don't have .cas files sent with the game so it will start generating non-functioning 1kb ones, make sure you don't end up with those in game! I did the items making procedure on a spare install and just copied the regenerated items.db and the new items I wanted over to my proper install.
You have to have entire contents of items folder in one place in the end btw, you can't have some in data/items and try and read others from packs, if you use mod-folder you need all the items in the mod-folder.
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