Wiki: monstermaker

monstermaker - Point Entity

This entity allows you to spawn monsters (or items/weapons).

Name (targetname) - Property used to identify entities.
Target on release (target) - Event to trigger when a monster is spawned.
Monster Type (monstertype) - The entity name of the monsters to be spawned (e.g. monster_headcrab).
Number of monsters (monstercount) - The maximum number of entities to spawn. -1 is infinite.
Frequency (delay) - Delay, in seconds, between each monster being spawned. If -1, a new monster will only be spawned after the previous has been killed.
Max live children (m_imaxlivechildren) - Maximum number of live children allowed at one time. Spawnings will be suspended until a monster dies. A value of -1 means infinite.
Childrens' Name (netname)

Start On (1)
Cyclic (4) - If this is enabled, the entity will activate then deactivate (used to spawn a single monster) instead of toggling it on or off when triggered.
Monsterclip (8) - If this is enabled, spawned monsters will not be able to pass through func_monsterclip brushes.

The Flags mechanism for this entity is doped:
- If targetname is blank, it will always spawn monster, no matter if "Start On" is enabled or not.
- If targetname is named and "Start On" is enabled, monster will not spawn as soon as the game starts. However, the best way to manage this entity is to give it a "target name" and set a trigger to activate it (once if Start On is disabled, twice if enabled). Doing so, its mechanics will normalize.
Monstermakers can be a bit of buggy, some of the monsters produced will not fade after death, and there are issues with the AI behavior of monsters spawned with a monstermaker.
The Childrens' Name (netname) basically assigns a name to the monster spawned, that way you can target the monster with a scripted_sequence, or sentence.
AI problems seem to be natural with grunts for some reason, and the only solution I have found is to transport them into the map from somewhere else. That way they retain their AI.
Spawning will be interrupted if you place a monstermaker too close to another so that both their monster's hitboxes can collide in game. Tip: you can use a "cycler" to render a model on Hammer Editor or insert a monster's typical entity and see its bounding box.