There’s math involved
If you make it your goal to learn one thing per day, the above video is a great way to kick things off for the New Year. Simonschereibt over on YouTube decided to break down the science of digital mushroom clouds, explaining how they are animated with evidence from multiple games, including Fallout 4.
He even digs into the textures to see how the developer did it, and how they basically touched up grey effects to craft the mushroom clouds.