Geometry Modification (or Geo-Mod for short) means, in short, the ability to modify geometry in real-time. Created by Volition Inc, Geo-Mod has been an icon of the Red Faction series since the start. Two versions of Geo-Mod has been released. Red Faction and later Red Faction II uses Geo-Mod 1.0 also originally known as RED (acronym for Realtime Environment Destruction). Later the name was given for the level editing program bundled with the Red Faction PC version, changing the acronym to (Red EDitor).
Red Faction: Guerrilla released in 2009 uses a new destruction engine named Geo-Mod 2.0. This engine abandons true geometrical modification in favor of using pre-broken meshes which fall apart when impacted.