functionality triggers/events : this level of dynamics is driven with a front-end system / Content Management System (CMS) it is ‘assets’ vs ‘presentation of…’
pooling logic is established to load assets needed per zone/level/character/vehicle ; then awakens and recycle them when needed.
an entire ‘ability’ system is needed to drive attachment logic such as ownership, local vs world based updates, transforms/locations rotations even scale or child/parenting
( Playmaker is the often cited resource ‘stepping-stone’ between engineer/designer authoring )
the state machine can trigger prefabs nested inside a character and there is an Event system [but I just disagree with doing it that way], or call animations and send out parameters like
left_foot = true or
left_footStep == 1.00
IMHO the low-level standards around these solutions are outside of just tech-art : When AD’s ask me about functionality I point to front-end and back-end engineers and mention meeting /w them + design to hammer out future goals and standards
 playing with formatting
Op-Ed - From my _mobile games_ experience...
This ‘functionality’ system is the backbone of gameplay; Incredible amounts of time are saved or destroyed between nearly every discipline at this step; It is not just gameplay, but the test and iterative playground.
Limits inside this feature return band-aid’s, re-design and feature creep. I recommend studios prioritize this portion : modular and low-level system.
See samples of how extensively this is handled at places such as Riot in their Tech section
one - Game data
two - Entity back-end
three - Even upgrading their particle tools