AdditiveDamageModifier

AdditiveDamageModifier

AdditiveDamageModifier makes Valheim resistance and weakness modifiers stack together instead of letting only the strongest modifier win.

The current development build targets Valheim 1.0.7 (Windows client build 25185596 / dedicated server build 25185644) and BepInExPack Valheim 5.4.2350. Older game binaries are not supported by this build. Existing mod configuration keys and translation formats are unchanged.

The 1.0 compatibility patch updates the six-argument item tooltip hook (including appended tooltips), processes the new NonPlayer damage channel without adding a player minimum setting or new adm_ effects, and repairs three obsolete constant-field accesses in the bundled ServerSync. See ServerSync repair details.

In vanilla, several sources of resistance and weakness do not cancel each other out. The game chooses one final modifier by priority. This mod changes that into an additive calculation, so every relevant modifier contributes to the final damage multiplier.

Adds visible adm_ status effects for testing, events, commands, and other mods. You can use addstatus command for testing.


Shows the effective modifier percent in tooltips and active effect UI.

CheckOut this mod to use training dummy for damage and resistance testing. https://thunderstore.io/c/valheim/p/sighsorry/TouchGrass/
Above is an example of RootArmor(+30%) + FeatherCape(+45%) + FireResistMead(-30%) = SUM(+45%) of fire damage with the mod's default setting.

Main Features

• Stacks resistance and weakness modifiers additively per damage type.
• Affects both players and creatures.
• Lets servers configure the percent value of each modifier tier.
• Adds player minimum damage caps so very strong resistance cannot always reduce player damage to 0.
• Adds visible adm_ status effects for testing, events, commands, and other mods.
• Shows the effective modifier percent in tooltips and active effect UI.
• Adds a Compendium page that explains the current server values, calculation, player minimums, and vanilla differences.
• Adds configurable fall damage cap and fall damage multiplier options.
• Keeps ServerSync version enforcement and synced gameplay config.

Additive Damage Examples

Default modifier values:

• Very Weak: +45%
• Weak: +30%
• Slightly Weak: +15%
• Slightly Resistant: -15%
• Resistant: -30%
• Very Resistant: -45%
• Immune: -100%

Example player modifiers:

Root Armor pierce resistance (-30%)
+ Berserker Mead pierce weakness (+30%)
+ Bonemass pierce resistance (-15%)
= pierce -15%

The player takes 85% pierce damage.

Feather Cape fire weakness (+45%)
+ Barley Wine fire resistance (-30%)
= fire +15%

The player takes 115% fire damage.

Creature resistances and weaknesses are additive too. A creature that is weak to pierce by +30% takes 130% pierce damage; a creature resistant by -30% takes 70%.

Player Minimum Damage Caps

Player damage has configurable minimum damage taken caps for these damage types:

• Blunt
• Pierce
• Slash
• Fire
• Poison
• Frost
• Lightning

The config option is named Player Minimum Damage Taken Percent - <damage type>. The default value is 10, so an immune or heavily resistant player still takes at least 10% of the original damage from those capped types. In the Active effects compendium, this same cap is shown on the additive modifier scale as MinTotal -90%.

Spirit intentionally has no player minimum cap because vanilla players are already immune to Spirit damage.

Status Effects

The mod registers 56 status effects named:

adm_<damage_type>_<modifier>

Supported damage types:

blunt, pierce, slash, fire, poison, frost, lightning, spirit

Supported modifiers:

very_weak, weak, slightly_weak, slightly_resistant, resistant, very_resistant, immune

Examples:

adm_blunt_very_weak
adm_fire_immune
adm_spirit_resistant

These effects can be added with commands such as:

addstatus adm_blunt_resistant

Each adm_ effect has a generated status icon, a readable HUD name without the adm_ prefix, and a percent label. Modifier icons use simple tier markers:

+1, +2, +3, -1, -2, -3

Tooltips And Compendium

Damage modifier tooltip lines can show the configured modifier percent, for example:

Damage modifier: Resistant VS Fire (-30%)

When the exact passive armor item is equipped, or the displayed status effect is currently active on the local player, the same line also shows the combined modifier for that damage type:

Damage modifier: Resistant VS Fire (-30% / Net -45%)

Net is the raw sum before the player minimum damage cap. Direct weapon and shield damage modifiers are block-only and are not included in passive Net; an Equip or Set status effect from those items is included while that effect is active.

Net is calculated at most once per tooltip generation and shared by its nested effect descriptions. Valheim can regenerate an item tooltip every frame while the inventory is open; this is not a cache for the entire time the tooltip is visible.

This non-compendium percent suffix is controlled by a client-only config option:

[1 - General]
Show Modifier Percent in Tooltips Outside Compendium = On

The Active effects compendium always shows fuller information, including the current Net for active effects and MinTotal when applicable: