I am trying to figure out how to make something like the Global Fog “Script” to appear like it is “rolling” in from a direction while it is growing higher and higher.
I have looked around on the internet but no luck.
Anyone have any idea on where I would start on this challenge of mine?
The idea is to have it look like a sand storm comming in.
I am grateful for all help.
particles?
or maybe can modify global fog shader, so that instead of taking distance to camera,
it takes distance from some other object… (so fog is going that way, when adjust distance)
asset store had some nice looking global fog also, it might have extra features…
I tried with particles but framerate goes down fast.
Sadly I have only disability pay so paid assets in the store is mostly a no.
I guess that I need to check the shader out and see if I can customize it as you said 
or how about just a big meshes, maybe with a bit animated vertices, and some particle texture, and move that in…
do you have some reference image how it should look like?
Well what I am looking for is somewhat like this :
I know it wont be exacly like that but it should be dark at the bottom and brighter at the top as the sunlight hits the top. It will go dark as in the clip when it is over the player and for some time. then it will just move on and go away again.
thats quite a fog… 
there is this plugin (although its also paid one), i would thing its still heavier than using particles…
how many particles/particle systems you had that it became too slow…?
I went in and looked at the package you gave me the link to and it seems to be really good. I just had to buy it now when it was on sale.
I will have to reduce food costs this month but it seems worth it :).
Installed and tested a bit and just have to say WOW. It looks nice and it seems good for the frame rate as well. Will try to use this in my project.
Thank you for the link!