It's for BtS.
I just want to replace the normal european units with these new ones. I'm going to use the chariot as an example to show my understanding.
Step 1: Copy existing chariot entry in Artdefines_Unit and make a new entry. (Any one?)
Step 2: Rename. (Where does the location go? Do I only need to copy location for the nif and kfm?)
Step 3: Add chariot under european in UnitArtStyleType.
Yeah... you're on the right track. You just need to realize if you're going to change ANYTHING about the game you're going to need to make a mod for yourself (I don't suggest altering the base files).
Step-1: Go to your "Civilization 4/Beyond the Sword/Mods" folder and create a new folder for your own mod... call it "marxengles" for example.
Step-2: Go to "Civilization 4/Beyond the Sword/Mods/marxengles" and copy any files you need/want-to-change/alter from Civ4 into here, keeping the same path as the original game... for units we're talking this: "Civilization 4/Beyond the Sword/Mods/marxengles/Assets/Art/Units", then add whatever you want... I guess add a "EuroChariot" folder here and drop the files in there.
Step-3: Copy existing chariot entry in Artdefines_Unit and make a new entry.
Step-4: Rename the entry to ART_DEF_UNIT_CHARIOT_NEW_EUROPEAN (There's a "Chariot_European" already, never make an exact dupe or you'll have problems!)
Step-5: You really only need to change 2 or 3 lines on-average... NIF/KFM/SHADERNIF... (sometimes you don't need to change the KFM line) do it like this in your example:
<NIF>Art/Units/EuroChariot/Chariot.nif</NIF> (points to your mod)
<KFM>Art/Units/Chariot/Chariot.kfm</KFM> (points to original or your mod... depending on custom unit used)
<SHADERNIF>Art/Units/EuroChariot/Chariot_FX.nif</SHADERNIF> (points to your mod)
Step-6: Add/alter chariot under "european" in UnitArtStyleType.xml. Make sure the name for all three ages matches whatever you added in the ArtDefines.xml... in this case "ART_DEF_UNIT_CHARIOT_NEW_EUROPEAN"
Almost there!
Step-7:
Start game... go to "ADVANCED" and "LOAD A MOD"... chose "marxengles" (it'll match the folder name of what you created in the BtS Mods folder!)
Step-8: choose any European nation to play and look-up the Chariot in the Civilopedia to make sure you did it right! Remember, adding flavor units this way only shows-up in-game for the nation/ethnic-group you assigned it to. The Civilopedia in the main menu will still show default units, but if you play as the correct nation, it will show in the Civilopedia in-game.
If you have any problems or "red blobs" you probably had a typo in the ArtDefines entry and/or used the wrong KFM file (check the authors instructions to make sure you use the correct KFM... most unit creators will tell you which KFM line to use... you can copy/paste it in the ArtDefines.xml).
Remember, doing this is addictive... next thing you'll know is that you change every darn ethnic unit in the game. I started with just changing a couple of European Swordsman and Horseman, now I'm doing every unit in the game (or so it seems).
If you get real bold, you can copy/paste the "European" category in the Civ4UnitArtStyleTypeInfos.xml, rename the entry "UNIT_ARTSTYLE_GERMAN" for instance, then change the Civ4CivilizationInfos.xml so that the Germans use the "ARTSTYLE_GERMAN" instead of "ARTSTYLE_EUROPEAN", and that's how you make nation-specific units.