Up, Still have no ideea how to do it.
A good example is a sandstorm. For example, in my FPS game, whenever you try to shot in a sandstorm, your bullet won’t go straight, but will go to left/right, depending on the wind direction. Now, I don’t want the bullets and grass to move the same way, so I need somehow to modify the power wind will execute on every part, including trees, grass, bullets or even players.