Ok figured it out. the 2D sprite doesnt need a geomtry and object file referring to a standard mesh.
But we are making a 3d sprite for the rain drop which will need its own geometry.con file in objects.rfa. The reason for doing this is so we can add collision physics to the rain. Currently, if you go into a hut while its raining you still get wet...
So either have to take the roof off to make it appear authentic, or the bloody roof has a lot of leaks. So the 2D will have to do for now.
i dont beleive its possible to make rain mapside only without touching objects.rfa and textures.rfa and play multiplayer. So i created me first mod using the BFV objects.rfa and changed it up and it works a treat.
Rain, rain, and more rain.