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Scalable Floats and Curve Tables

FScalableFloat is GAS's primary mechanism for level-based scaling. It pairs a raw float value with an optional curve table reference, producing Value * Curve[Level] at runtime.

FScalableFloat

Properties

Property Type Description
Value float The raw coefficient. If no curve is set, this is the final value.
Curve FCurveTableRowHandle Reference to a row in a UCurveTable. Evaluated at the specified level.
RegistryType FDataRegistryType Optional: Data Registry containing the curve. If set, Curve.RowName is used as the item name.

Evaluation

At runtime, GetValueAtLevel(Level) computes:

FinalValue = Value * CurveTable[RowName].Eval(Level)

If no curve is set (IsStatic() == true), the raw Value is returned directly.

Key Methods

Method Description
GetValueAtLevel(float Level) Returns Value * Curve[Level]. The primary evaluation method.
GetValue() Returns GetValueAtLevel(0). Convenience for level-independent lookups.
AsBool(float Level) Returns true if the evaluated value is non-zero
AsInteger(float Level) Returns the evaluated value cast to int32
IsStatic() Returns true if there is no curve reference (raw float only)
SetValue(float) Sets the raw Value without changing the curve reference
SetScalingValue(float, FName, UCurveTable*) Sets both the value and curve reference
IsValid() Returns false if the curve reference is broken

Where FScalableFloat Appears in GAS

FScalableFloat is used extensively throughout the Gameplay Effect system:

Location Property What It Controls
FGameplayModifierInfo ModifierMagnitude (when using ScalableFloat type) Modifier magnitude at a given GE level
UGameplayEffect DurationMagnitude How long a HasDuration effect lasts
UGameplayEffect Period Time between periodic executions
FGameplayAbilitySpecConfig LevelScalableFloat Ability level granted by AbilitiesGameplayEffectComponent
UChanceToApplyGameplayEffectComponent ChanceToApplyToTarget Probability of GE application (0.0 to 1.0)
Various ability tasks Duration/delay parameters Task-specific timing

Curve Tables

A UCurveTable is a collection of named curves, each mapping a float input (the "level") to a float output.

Creating a Curve Table

  1. Content Browser > Add > Miscellaneous > Curve Table
  2. Choose Rich Curve (for interpolated float curves) or Simple Curve (for linear segments)
  3. Add rows — each row name becomes a key you reference from FScalableFloat
  4. Add columns for each level (1, 2, 3, ...) and set the values

  1. Create a CSV file with a header row of level numbers:

    ---,1,2,3,4,5
Damage,10,15,22,30,40
Cooldown,5.0,4.5,4.0,3.5,3.0
ManaCost,20,25,30,35,40

  2. Content Browser > Import, select the CSV, choose CurveTable as the import type

  3. Configure interpolation type (Constant, Linear, or Cubic)

Linking a Scalable Float to a Curve Table

In a Gameplay Effect's modifier:

  1. Set Magnitude Calculation Type to Scalable Float
  2. Set the Value field (the multiplier coefficient, often 1.0)
  3. In the Curve dropdown, select your curve table and row
  4. At runtime, the GE's level is passed as the curve input

Global Curve Table

You can designate a global curve table in Project Settings > Gameplay Abilities Settings > Global Curve Table. This table is loaded once at startup and available to all FScalableFloat references. Useful for centralizing all scaling data in one asset.

Data Registry Integration

FScalableFloat supports FDataRegistryType as an alternative to direct curve table references. When RegistryType is set:

  1. The Curve.RowName is used as the Data Registry item name
  2. The curve table reference itself may be empty — the registry resolves it
  3. This enables async loading and late-binding of curve data

This is an advanced feature primarily useful for large projects that need lazy-loaded scaling data.

Practical Patterns

Flat Value (No Scaling)

Set Value to the desired number, leave Curve empty. The value is constant regardless of level.

Value: 25.0
Curve: None
Result at any level: 25.0

Level Curve Only

Set Value to 1.0, set Curve to a row that contains the actual values per level.

Value: 1.0
Curve: DamageTable.Fireball
Level 1 → 1.0 * 50  = 50
Level 5 → 1.0 * 120 = 120

Coefficient + Curve

Set Value to a coefficient, set Curve to a normalized progression curve. Useful when multiple abilities share the same curve shape but different magnitudes.

Value: 2.5
Curve: SharedProgression.Linear
Level 1 → 2.5 * 10 = 25
Level 5 → 2.5 * 30 = 75

This allows designers to tune individual ability magnitudes (the Value) independently from the overall scaling curve.