I absolutly hate the LGV méditeranée scenery so I want to try to make it better but i have no idea how to make a scenery update mod, could someone help me?
There is a very good Overlay tutorial on train sim wiki, you can just google for it and then there is it. It only explains how to make an overlay and after that select the foliage edit mode and select the stuff you want to add at the left side.
Adding Scenery Overlays | Train Sim Community Wiki Its the first steps, the cooking process can be found here in the forums as a pinned post from Alex. Edit: I didnt test if if the cooking works with it like explained, so could or couldnt be.