Stat Interactions

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Modifiers to stats of Classes and Equipment in Steambirds Alliance change these stats in predictable ways. These methods of application are informally called Stat Interactions.

Types of Stat Modifiers

  • Percent increases (+X%) are the most common modifier type, appearing on equipment, classes, Upgrades and Pilot Skills, among other sources. +X% modifiers stack additively, resulting in diminishing returns as more modifiers of this type are applied to the same stat.
  • Percent reductions (-X%) are somewhat less frequent than percent increases. Unlike +X% modifiers, -X% modifiers stack multiplicatively, preventing stats from being reduced to 0 unless a -100% modifier is in effect.
  • Flat increases (+X) are generally applied after all other modifier types. Though this allows them to ignore -X% modifiers completely, this also prevents them from being augmented by +X% modifiers
  • Flat reductions (-X) are generally applied before all other modifier types. -X modifiers may sometimes turn positive stats into negative stats, resulting in unusual behavior.

General Stat Interactions

The following order of operations has been observed concerning the application of multiple modifiers to a particular stat:

  1. The stat starts at a set value, called its base value.
  2. -X modifiers are applied to the base value.
    • Example: An Old Faithful with Laser 2-A (-0.5/s Steam Recharge while firing) has its Steam Recharge reduced to (0.4/s - 0.5/s =) -0.1/s while firing a Laser.
  3. Class-specific +X% modifiers are applied to the result of (2).
    • Example: A Paladin normally has a Steam Recharge of (0.4/s * 4 =) +1.6/s due to its class-specific +300% Steam Recharge modifier. With Sword 2-A (-1/s Steam Recharge while firing), Steam Recharge is reduced to [ (0.4/s - 1/s) * 4 =] -2.4/s while firing a Sword.
  4. If the result of (3) is not negative, all other +X% modifiers are added together, then applied to the base value as a single multiplier (this is referred to as additive stacking) to obtain the corresponding stat increment. This increment is then added to the result of (3).
    • Example: A Paladin with Sword 2-A (+50% Steam Recharge while not firing) and Level 5 Armor 2-A (+55% Steam Recharge) gains {0.4/s * [(50% + 55%) / 100% ] = 0.4/s * 1.05 =} 0.42/s Steam Recharge while not firing. This is added to the Paladin's initial 1.6/s Steam Recharge to produce a final value of 2.02/s.
  5. -X% modifiers are applied as individual multipliers to the result of (4) (this is referred to as multiplicative stacking).
    • Example: A Quad with Level 10 Machine Gun 1-A (-30% Cooldown) and Level 5 Quad 1-A (-45% Cooldown) has the Cooldown of its Machine Gun reduced to {100% * [ (100% - 30%) / 100% ] * [ (100% - 45%) / 100% ] =} 38.5% of its base value, a net 61.5% Cooldown reduction.
  6. +X modifiers are applied to the result of (5) (after -X% modifiers have already been applied) to produce the final value.
    • Example: An Old Faithful using a Blaster has Old Faithful 1-A (-100% Steam Recharge while above 90% Armor) and Level 5 Blaster 1-B (+1.0/s Steam Recharge while not superspeeding). While not superspeeding and above 90% armor, the Old Faithful has { 0.4/s * [ (100% - 100%) / 100% ] + 1.0/s = 0/s + 1.0/s =} +1.0/s Steam Recharge.

Special Stat Interactions

Armor

Modifiers to Armor deviate from the standard order of operations in the following two ways:

  1. +X Armor granted by the equipped Armor item is added first to the plane's initial base Armor (15 for single-stick aircraft, 10 for twin-stick aircraft). All other modifiers treat the resulting sum as the base value when applying their effects.
  2. +X Armor granted by the use of Armor Stiffeners is added after +X% modifiers, but before -X% modifiers.

Damage

The Damage stat is a percent-based modifier of bullet damage (and Bash maneuver damage) rather than a conventional stat. As a result, Damage has a simpler set of stat interactions:

  • +X% modifiers, including element-specific modifiers from upgrades, are simply added to Damage as-is.
  • -X% modifiers apply multiplicatively to Damage after increases from +X% modifiers have been included.

Proportional Relationships

Modifiers to certain stats also apply to specific related stats, preserving particular stat ratios in the process. For a given X / Y proportional relationship, changes to X result in proportional changes to Y (however, changes to Y do not also result in proportional changes to X):

  • Armor / armor (only on Armor changes)
  • Max Steam / Steam (only on Max Steam changes)
  • Max Speed / Super Speed (always)
  • Bullet Speed / Range (always)