Entities are elements of a map
that perform certain functions. While brushes
make up the structure of a map, entities define all aspects of a map that make a map playable and interactive.
There are two different types of entities: point entities
and brush entities
. Brush entities are brushes that perform functions beyond being the static geometry of a level, such as doors and triggers. Point entities are used to manage all other game logic, including playing sounds, defining level starts/ends, placing enemies and models, spawning items, and much more.
game has a different set of entities available to it. Specific entity information can be found in TWHL's Entity Guides