From one game to a platform
In the 1990s id Software licensed the Doom and Quake engines to other studios. Half-Life was built on a modified Quake engine. In 1998 Epic Games released Unreal and began selling its engine as a product.
Today's big three
- Unreal Engine 5 offers Nanite (huge amounts of detail) and Lumen (dynamic lighting). It is also used in film and architecture.
- Unity powers a large share of mobile and indie games.
- Godot is completely free and open source, popular with smaller teams.
In-house engines
Big studios often have their own technology: Rockstar uses RAGE (also for GTA 6), Ubisoft Anvil and Snowdrop, Valve Source 2 (Counter-Strike 2, Deadlock).