Banishers - Unreal Engine 5 - Fog Of War

Here is a breakdown of the Fog of War feature from Banishers: Ghosts of New Eden at DONT'NOD.
This feature was developed in collaboration with Technical Artist Florine Fouquart, and used by Level Designer Nicolas Zelvelder.
We created a blueprint that hold Linear splines components that define each zone's borders inside the map actor.
When the player discovers a new zone, the actor updates, and all splines corresponding to discovered zones are triangulated. These triangles are then captured in a Render Target Texture. Another texture copies and blurs the first one, making the reveal look smooth.
This blurred texture is used as a mask in the fog shader.
There are two planes of fog creating a parallax effect. The first one is "transparent", adding small clouds in the discovered zones, while the second is "masked" to ensure that undiscovered zones remain hidden.
https://www.artstation.com/nicolaszelvelder