Events and Event Handlers Overview

Parent Emitter

On the parent emitter, under Particle Update, add a Generate Event based on the type of event you want. The Generate Event can be added Particle Spawn so long as you dismiss the error issue. Location events can be combined to create complex interactions. Types of events include:

• Location: Each particle will generate location information during its lifetime.
• Death: Each particle will generate an event at the end of its lifetime. Can be used to trigger another emitter's effect.
• Collision: Each particle will generate an event when they collide with an actor. To add a collision event, you must first add a Collision module to the emitter.

Child Emitter (follows parent)

On the child emitter, add an Event Handler Properties module if not present and then a Receive Event module. Under Event Handler Properties is where you will add the Receive Event module. In the Event Handler Properties, the "Source" dropdown will define which Generate Event your particles are affected by. Execution Mode determines which particles are affected (Execution will send the information to already living particles, Spawned will send it only to those particles not yet spawned), Max Events Per Frame is the number of times the event occurs per frame, and the Spawn Number defines how many particles are spawned (if the event spawns particles). After the properties are set, you select a Receive Event that matches the generated event module you placed in the Particle update group of the emitter that generates the event.

Tricks

Add a Generate Location Event Spawn module that is a duplicate of Generate Location Event without complicating things that just passes along the event data we care about. Then use this on a Particle Spawn generating the event exactly once and having the child emitter spawn particles in response to that, not worrying about the generation of events over time.