# Authoring Effects

A designer-focused guide to creating, configuring, and balancing status effects without writing code.

# Creating a New Effect

In the Content Browser, navigate to where you want to store effects (recommend Content/Effects/ or Content/SFX_Defs/).
Right-click → Miscellaneous → Data Asset.
Select AP StatusEffectDefinition as the class → click Select.
Name the asset with the SFX_Def_ prefix: e.g., SFX_Def_Chill, SFX_Def_Fortify.
Double-click to open and configure the Details panel.

Naming Convention

Using the SFX_Def_ prefix makes effects easy to filter in the Content Browser and keeps them separate from other Data Assets in the project. All demo content uses this convention.

# Effect Tag

Every effect must have a unique Gameplay Tag set as its EffectTag.

# Recommended Tag Hierarchy

Effect
├── Buff
│   ├── Effect.Buff.Regeneration
│   ├── Effect.Buff.SpeedBoost
│   ├── Effect.Buff.Shield
│   └── Effect.Buff.Fortify
├── Debuff
│   ├── Effect.Debuff.Poison
│   ├── Effect.Debuff.Burning
│   ├── Effect.Debuff.Slow
│   └── Effect.Debuff.Stun
└── CC
    ├── Effect.CC.Frozen
    ├── Effect.CC.Sleep
    └── Effect.CC.Fear

Tags are registered in Project Settings → Gameplay Tags or via the plugin's Config/Tags/StatusFXTags.ini.

Tag Uniqueness

Two definitions using the same EffectTag will conflict — the system cannot distinguish between them. Always use a unique tag per effect type.

# Duration Types

Type	Use When	Key Property
Timed	Effect should expire automatically	Set `BaseDuration` (seconds)
Infinite	Effect lasts until explicitly removed (e.g., a passive trait)	No duration needed
Instant	One-shot effect — fires `OnEffectApplied` once with no ongoing state	No duration or stacking needed

# Choosing a Duration

Short (1–3s)   — Crowd control, brief interrupts (Stun, Fear)
Medium (5–15s) — Damage-over-time, moderate buffs (Poison, SpeedBoost)
Long (30s+)    — Persistent buffs, environmental hazards (Regeneration aura)
Infinite       — Permanent states, passive bonuses, custom-removed effects

# Tick Interval

Set TickInterval to have the effect fire OnEffectTick periodically. Common uses:

TickInterval	Use Case
`0.0`	No ticking (default) — effect applies once on application
`1.0`	Damage/heal per second (poison, regeneration)
`0.5`	Fast DoT, rapid resource drain
`3.0`	Slow periodic pulse, environmental tick

Server Only

OnEffectTick fires on the server only. Bind to it on the server to apply actual gameplay consequences (damage, healing). For client UI, use bIsTicking from the snapshot to show a pulsing indicator.

# Stacking Policies

Choosing the right stacking policy is the most important design decision for each effect.

Behavior: Reapplication resets the duration timer. Stack count is always 1.

Use for: Buffs and debuffs where only the most recent application matters — speed boosts, damage buffs, shields.

Example — Speed Boost:

Player applies Speed Boost (10s).
Player applies Speed Boost again at 6s remaining.
Result: Duration resets to 10s. Stack count stays at 1.

Behavior: Each application adds its full duration to the remaining time (up to no explicit cap by default).

Use for: Effects that "stack up" over time — channeled heals, sustained buffs from repeated casts.

Example — Hot Spring Aura:

Player enters hot spring: Regeneration applied (15s).
Player stays: Regeneration applied again → now 30s remaining.
Each second the player stays, more duration accumulates.

Behavior: Each application adds one stack (up to MaxStacks). Duration is shared and refreshes on each application.

Use for: Escalating effects — poison that deals more damage per stack, bleeds, charge-based mechanics.

Example — Poison (MaxStacks: 5):

Hit 1: Poison × 1 (10s)
Hit 2: Poison × 2 (10s, refreshed)
Hit 5: Poison × 5 (10s, refreshed) — maximum damage, maximum stacks

Your game logic reads GetStackCount() and scales damage accordingly.

Behavior: Each application creates a completely separate tracked instance with its own duration.

Use for: Effects where each source is tracked separately — multiple projectile DoTs, layered shields, multi-source bleeds.

Example — Layered Shield:

Ability A applies Shield (15s).
Ability B applies Shield (10s).
Two separate shields exist simultaneously; they expire independently.

Configure GlobalMaxIndependentStacks in Project Settings as a safety cap (default: 50).

Behavior: Delegates all stacking logic to a UAP_StackingResolver subclass you provide.

Use for: Complex or unique stacking that doesn't fit the built-in models — charge systems, diminishing returns, gear-driven scaling.

Create a Blueprint subclass of UAP_StackingResolver, override ResolveStacking, and assign the class to CustomStackingResolverClass on the definition.

# Interaction Rules

Effects can interact with each other in two ways:

# Removes Effects With Tags

When this effect is applied, remove any currently active effect whose EffectTag is in this container.

Example: Antidote

RemovesEffectsWithTags: Effect.Debuff.Poison, Effect.Debuff.Disease
When Antidote is applied, all poison and disease effects are removed.

# Blocked By Effects With Tags

This effect cannot be applied while any effect with these tags is active.

Example: Frozen (blocked by Invulnerability)

BlockedByEffectsWithTags: Effect.Buff.Invulnerability
While the target has Invulnerability, applying Frozen silently fails.

# DataTable Rules (Complex Interactions)

For interactions that require immunity grants on removal, use a DataTable in Project Settings:

Column	Value
`SourceTag`	`Effect.CC.Frozen`
`TargetTagsToRemove`	`Effect.Debuff.Burning`
`bGrantImmunityToRemoved`	`true`
`ImmunityDuration`	`3.0`

Result: Applying Frozen removes Burning and makes the target immune to Burning for 3 seconds.

# Immunity on Expiry

Enable bGrantImmunityOnExpire and set ImmunityDuration to automatically grant immunity after an effect ends naturally.

Example: Stun with Tenacity

Stun expires after 3 seconds.
bGrantImmunityOnExpire: true, ImmunityDuration: 5.0
The target is immune to Stun for 5 seconds after recovery — prevents stunlock.

This is a common pattern in action games and MOBAs (crowd control diminishing returns).

# Icon Setup

Set the Icon property on each definition to a 64×64 UTexture2D. The demo ships with 64×64 PNG icons for all 31 included effects — you can use these as a starting point or as placeholders while producing your own art.

Import icons via Content Browser → Import or by dragging PNG files directly into the editor.

# Validation Warnings

The editor will show warnings in the Compiler Results panel if a definition has invalid configuration:

Warning	Cause
Missing `EffectTag`	`EffectTag` is not set — the effect cannot be identified
`CustomStackingResolverClass` not set	Policy is `Custom` but no resolver class is assigned
`TickInterval` < 0	Negative tick interval is invalid
`MaxStacks` < 0	Negative max stacks is invalid

Fix any warnings before using the definition in gameplay.

# Balancing Tips

Designer Notes

Keep TickInterval at 1.0 for damage-per-second DoTs — it makes math obvious and easy to tune.
Use MaxStacks liberally with Stack Intensity effects — without a cap, effects can grow without bound.
For crowd control, always set bGrantImmunityOnExpire: true with a reasonable ImmunityDuration to prevent stunlocks.
Test stacking interactions in the demo map using the keyboard shortcut keys before integrating into your game.

AfterPrime Systems — Building the Gameplay Foundation