VMaps are "Visibility Maps" or collision data. This is where the world stops being a flat height-map and becomes a 3D space.

They ensure that if you jump off a bridge, the server knows exactly when you hit the floor below. 4. MMaps (Movement Maps)

MMaps require VMaps as a base and are generated with mmaps_generator . Without MMaps, creatures run in straight lines, clip through objects, or fall off cliffs.

They tell the server where the terrain exists so players don't fall through the floor.

. To Elias, these are the "physics of logic." Without VMaps, a dragon's breath would pass through solid castle walls, and a player could walk through a mountain as if it were mist. When Elias installs these, the world gains weight. Walls become solid, and roofs finally keep out the digital rain. Then there are the MMaps (Movement Maps)

Studying how Blizzard's original engine handled thousands of players at once.

Here is a story of how these files come together to create a living, breathing Azeroth. The Ghost in the Machine