i only know that my versions of rage of dark gods and botet the arrow impacts are invisible or very faint and translucent.
i found the solution. you will look in...
data/model_effects/textures---- look for siege_rocket_launcher.texture
I know it sounds totally rediculous that such a texture would be used for the ground impact arrow model but it is.
2)you can copy the mtw2 original file ( medieval II total war/data/model_effects/textures/siege_rocket_launcher.texture..... and paste it in the (Rage of Dark Gods or BOTET) data/model_effects/textures folder. the computer will ask you if you want to replace the existing file with the one you are pasting and you of course will respond yes.
It should work
You could also simply delete the siege_rocket_launcher.texture file from your mod directory and it will then parse from the original medieval total war database because whenever a file is missing in a mod than the game will begin looking into the original game database to find the file.
This texture file as it exists in the rage of dark gods and botet mods appears to be bugged somehow. which is why using the original texture file fixes it.