At Remedy we didn’t had tools to populate with VFX a large area.
For AW2 we got LUA in the engine, giving us more power and bypassing the lack of support for VFX from the tools team.
Inspired by the article of Ghost of Tsushima I created a series of systems to populate the world with VFX. Our Particle system implementation was really limited and a lot not possible to edit.
To make it more systemic, I made a LUA tools that allowed us to using triggers on the sky to spawn leaves, birds and water droplets after the rain, based on rules set reading the Weather System made by Daniel Konzieck. Since the new Wind they made was not working for the particles I made multiple effects with different speed that I was rotating and playing depending on the wind direction and intensity
Another tool allowed you to place large triggers on the ground, that will make some raycast over time, to check where the ground is and their physic material. This was allowing to spawn dust/sand/leaves/grass when there was wind and was not raining, and a pocket of insects randomly on the environment. The emitters where also rotating based on the wind. And made some textures for the sand and leaves.
I also made a system that spawned a VFX between random particle systems and nothing, that was made for the Dark Place so each time would feel a bit different.
I populated all the Brightfalls and nursing home area with all that.
Another of my task was to make the lookdev for the mist and fog pockets, I worked on the area behind the nursing home for this, but never push it to the rest of the game during my time on the project.
I also made the first Cinematic benchmark, and exploration on how we could blend between the environmental VFX and the extra cinematic VFX to give a better mood an feeling on them, That was made in the DarkPlace where I made water leaks on the bridge and building structures using Daniel Shader and the AC and Manhole Steam, I made similar VFX for the Bunker Overlap.
After I left as far as I know Matti, Jose, Elina John and Manuel populated the rest of the world, polished, made more and bug fix, finishing the game as you saw it.

Lead VFX:
https://www.artstation.com/richterteer
Team
https://www.artstation.com/doosead
https://www.artstation.com/dam
https://www.artstation.com/mckennafx
https://www.artstation.com/elineslingerland
https://www.artstation.com/josemorval
Manuel Köster
Matti Hämäläinen