the misanthrope gas engine replaces minecraft air with a new block called mge:atmosphere, the atmosphere blocks do real gas simulation inside of it's NBT data, with gasses spreading to their 26 neighbors, gasses have weight and move up or down in air currents, and based on temperature, this has compatibility with project atmosphere, the different gasses in an atmosphere block also decide whether or not the player or any other entity can breathe in a given area, the default atmospheric gasses for each dimension are data based, and on base this has compatibility with blue skies, prim's upside down mod, cracker's witherstorm, edenring, ceillands deeper darker, undergarden, dimensional doors, and the aether
Also on curseforge
