Gameplay Effects

The BP_GameplayEffect class in the Advanced Abilities Framework is a Blueprint class designed to modify attributes in Action RPGs, supporting instant, timed, or periodic changes such as damage, buffs, or debuffs. It enables developers and designers to create data-driven effects that alter gameplay states, like reducing health or boosting speed, while integrating with the BP_AdvancedAbilitySystemComponent. This class addresses the need for a flexible, modular system to manage attribute changes and associated visual/audio cues, streamlining dynamic gameplay mechanics.

Basic Usage

The BP_GameplayEffect is used by creating child Blueprints and applying them via the BP_AdvancedAbilitySystemComponent. Below are the primary methods for interacting with it in Blueprints.

1. Apply Effect:

   • Purpose: Applies the effect’s attribute changes and triggers associated cues.
   • Usage: Override in a child Blueprint for custom application logic.

2. Remove Effect:

   • Purpose: Removes the effect and performs cleanup.
   • Usage: Override for custom removal logic; called automatically for timed effects.

3. Can Apply Effect:

   • Purpose: Checks if the effect can be applied based on tags and conditions.
   • Usage: Override to add custom validation logic.

4. Apply Gameplay Effect By Class:

   • Purpose: Applies the effect from BP_AdvancedAbilitySystemComponent.
   • Usage: Call within an ability to trigger the effect.

Key Properties

Property Name	Purpose
Duration Policy	Enum (Instant, Infinite, Has Duration) defining how long the effect lasts; set to Has Duration for timed effects.
Duration	Sets the effect’s duration in seconds; requires Duration Policy set to Has Duration.
Period	Defines the interval (in seconds) for periodic effect applications (e.g., poison damage).
Modifiers	Specifies attribute changes (e.g., reduce Attribute.Health by 10).
Executions	Defines custom logic to execute when the effect is applied (e.g., damage calculations).
Application Required Tags	Requires the owning actor to have all these tags for the effect to apply.
Application Blocked Tags	Prevents effect application if the owning actor has any of these tags.
Granted Abilities	Grants specified abilities when the effect is applied.
Stacking	Defines how multiple applications of the effect stack (e.g., add stacks).
Gameplay Cues	Links to BP_GameplayCue or BP_GameplayCueActor for visual/audio feedback.

Key Concepts

Data-Driven Attribute Modification

The BP_GameplayEffect uses a data-driven approach, allowing designers to configure attribute changes via properties like Modifiers and Duration. This eliminates the need for extensive scripting, enabling rapid effect creation.

• Purpose: Simplifies attribute management for dynamic gameplay.
• Usage: Set Modifiers and Duration Policy in the Details panel to define effect behavior.
• Benefit: Empowers designers to create effects without coding.

Effect Duration and Periodicity

Effects can be instant (e.g., damage), infinite (e.g., permanent buffs), or timed with periodic applications (e.g., poison). The Duration Policy, Duration, and Period properties control these behaviors.

• Purpose: Provides flexible timing for effect application.
• Usage: Configure Duration Policy to Has Duration and set Duration and Period for timed effects.
• Benefit: Supports diverse gameplay mechanics like DoTs or temporary buffs.

Gameplay Cue Integration

The BP_GameplayEffect can trigger Gameplay Cues (e.g., BP_Niagara_ImpactEffect) to provide visual or audio feedback when applied, enhancing immersion and clarity.

• Purpose: Synchronizes effects with player-facing feedback.
• Usage: Add Gameplay Cues in the Details panel to link effects like particles or sounds.
• Benefit: Streamlines effect presentation with minimal setup.

Best Practices

• Workflows:
  • Use the GE_ naming convention for child Blueprints (e.g., GE_Poison) to maintain clarity.
  • Test effects with default configurations (e.g., GE_DamageEffect) before adding custom logic.
  • Use Instant effects for one-off changes like damage or healing.
  • Use Executions for advanced calculations that can’t be achieved through basic modifiers.
  • Leave Modifier ID blank — the system will generate a unique ID automatically.
• Pitfalls to Avoid:
  • Ensure Duration Policy is set to Has Duration for timed effects, or they won’t expire.
  • Don’t set Period too low (<0.5s) to avoid performance issues with frequent ticks.
• Performance Considerations:
  • Minimize Period frequency for periodic effects to reduce tick overhead.
  • Use Gameplay Cues sparingly for frequent effect applications; prefer BP_GameplayCue over BP_GameplayCueActor for frequent effect applications.