Example of typical usage to detect if the area of a trigger is seized by BLUFOR:
Create a trigger configured as:
This trigger evaluates if BLUFOR is dominating in the area and depending on the level of domination it needs to be hold for time from min to max set in time out (in seconds, only Time out style really makes sense for this trigger type, do not use it with Countdown style).
If a side has very strong dominance, only min timeout is needed. If it has a marginal dominance, max timeout is needed.
Whenever enemy has fired, the counter is reset - this means as long as there is any enemy fighting, the area is not considered seized even when there is a strong dominance.
If Detected by… is set, only units known to the side are used for estimating the level of control so the designer must ensure that entire trigger area is well known to the seizing side before considering the area secured (or create multiple triggers that need to be active at the same time).
How is one side dominating in the trigger? By being stronger than the enemy. Hard to describe more in detail - one tank or one chopper is much more force than a soldier, even different soldiers vary in force.
Source bis forums - Suma.