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The exact definition of the term trigger, when used as a verb, is somewhat flexible. In fact, its usage is downright sloppy, from a technical standpoint. As both a noun and a verb, confusing statements are inevitible unless we know, or at least decide, on a consistent definition.

In basic terms, something is considered to be triggered when its condition is altered by a dynamic situation. There, that really wasn't so hard. The trick, however, is in the usage.

It is easy to fall into the trap of abbreviating a recipe to save time and space, under the assumption that other folks "know what you're talking about." However, in the hands of the uninitiated, such abbreviations can lead to confusion. For example, most of us who are familiar with UnrealEd conventions have no difficulty understanding a statement such as, "The TriggerLight is triggered by the Mover." However, this statement is not literally true. TriggerLights cannot be triggered by Movers, but alternatively Movers can... "trigger an Event which matches the Tag of a TriggerLight." Notice how a 'simplification' in experienced hands is a missing key piece of information to the inexperienced.

In fact, this is technically unprecise. It's indeed the mover itself that triggers something else (where the mover's Event matches the other thing's Tag. The notion of an "event" being brought into life that starts going around and touching other actors with matching Tags might be handy to think of, but it's technically far from the truth. I don't agree that leaving the Event/Tag connection out is "unprecise" – the notion of having some actor trigger another actor implies that connection, just like "subtracting a cube" implies the creation of a red builder brush of that shape. (Don't get me wrong, somewhere the Event/Tag thing must be described, of course, but I'd rather not speak of a lack of precision when it's being implied in the term "triggered.") —Mychaeel

I therefore recommend that such abbreviations or shortcuts be avoided when using trigger as a verb. However, if the only point in an explanation is to show relationship between cause and effect, I suggest using another word such as "control," as in, "The TriggerLight is controlled by the Mover." Note that although this doesn't explain how the control is achieved, it is at least an accurate statement.


"These Light (UT)s are triggered by the Dispatcher
"The Dispatcher triggers multiple events which control these Light (UT)s.

I agree in principle that the word "triggered" is over-used, and often used imprecisely. I'm not sure I agree with the detail. After all, when a TriggerLight reacts to an event, it's because Trigger() function has been called – it therefore seems natural to describe this as "triggering", just as when the Touch() function is called we'd say the actor has been touched. – Tarquin

By saying that one actor "triggered" another, do we assume a certain degree of understanding in the reader (that an event and a tag are involved in the process)? What I like about speaking of events as entities is how it allows that the trigger could affect any number of other actors with the matching tag, whereas a statement such as "This actor triggers that actor" could, to a learner, imply that there is some kind of exclusive relationship. I admit that the distinction is borderline anal-retentive, and after reading your comments I'm afraid my conventions may not hold water on the scripting side, of which I have no knowledge. Any definition that appears on this page should be true 99% of the time, so I'm all for cleaning it up.Aedis

Maybe it'd be a good idea to rename this page to "Triggering" and merge the content of Tag and Event into it, and then to create redirection pages for Tag and Event. —Mychaeel

merging would certainly be good. Not sure which is the best name though. Another example of woolly terminology: "the player triggers the trigger"... I've done this one myself :(Tarquin

I agree that Tag and Event should be part of a single lesson. A less jargony title than "Triggering" might be clearer. "Working with Events" perhaps, or "Dynamics & Interactivity."Aedis

I've been personally settling for the following terminology: "A player touches a trigger" – (hence) "an event is fired" – (hence) "an actor is triggered" (by the event that was fired by the player touching a trigger). Saying "a player triggers the trigger" is probably not just unprecise but wrong since it implies (to me) "the player touched a trigger (which fired an event) which triggered a trigger (thus switching its bEnabled)" – perfectly possible, but uncorrect if you actually just meant "player touched a trigger, firing an event." —Mychaeel

Exactly. Touching and Triggering a Trigger are two very different things. —Tarquin

What about "Trigger Event"s (for distinction from the "event" keyword in UnrealScript)? —Mychaeel

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