A model is a specific kind of visual element in the GoldSrc
engines. Stored in their own separate files, models are capable of greater detail and are more dynamic than brushes
. Models are used widely throughout mapping, including enemies, items, viewmodels
, decorations and other players.
Sometimes models are used simply to create finer details than brushwork alone is capable of. Source mapping in particular tends to make heavier use of models in this way.
Models are stored as .mdl files, and can have multiple textures, animations and bodies. You can view .mdl files and see their contents (animations, bodies, textures) with a model viewer such as Jed's Half-Life Model Viewer