DiveIn

Adds diving and swimming for players and configured creatures.

Normally mobs can't follow you underwater. So players with diving mod players can just attack mobs from above or below without getting hit. This mod changes that.
Also added a diving mechanic for players with configurable stamina drain according to depth

Configured mobs can attack you! No more hiding under their bellies.

Idle mobs would swim within the configured range

Recommend to use with RtDOcean. There is configured sample for it.

Player Diving

• Unlike vanilla Valheim, stamina regeneration while swimming or diving can be enabled through config.
• Extra stamina drain can scale with depth. Deeper water becomes more expensive than staying near the surface.
• Use equipment in water except that is in blacklist.

Creature Diving

• Configured monster prefabs stop avoiding water and can navigate underwater.
• Idle monsters use passive depth profiles and slowly drift within their assigned depth range.
• Alerted or chasing monsters adjust depth toward their target within global depth limits.
• Underwater pathing uses route checks and steering avoidance samples instead of blindly forcing success.
• A single Dive AI Quality slider trades CPU cost for smoother underwater movement.

DiveIn.yaml

This file defines which monsters can dive and what passive depth band each monster uses.

# Monster dive configuration for DiveIn.
# Unknown keys and duplicate keys are treated as errors and keep the previous applied settings.

surface_patrol: # You can use any group name. Add your own groups
  passive_min_depth: 0 # Shallowest passive dive depth used while the monster has no target and is not alerted.
  passive_center_depth: 10 # Center depth used by the passive sine-wave swimming pattern.
  passive_max_depth: 20 # Deepest passive dive depth used while the monster has no target and is not alerted.
  active_depth_adjust_speed: 2 # How quickly this group adjusts swim depth while alerted or chasing a target.
  prefabs: # Monster prefab names assigned to this passive profile group.
    - Leech
    - Abomination
    - Serpent
    - BonemawSerpent

mid_water:
  passive_min_depth: 0
  passive_center_depth: 15
  passive_max_depth: 30
  active_depth_adjust_speed: 2
  prefabs: []

deep_patrol:
  passive_min_depth: 10
  passive_center_depth: 20
  passive_max_depth: 30
  active_depth_adjust_speed: 2
  prefabs: []

## Mod prefabs sample

mods_surface:
  passive_min_depth: 0
  passive_center_depth: 10
  passive_max_depth: 20
  active_depth_adjust_speed: 2
  prefabs:
    - Neck_RtD
    - Animal_Dolphin_RtD
    - Animal_Cod_RtD
    ...

Notes:

• If the same prefab appears in multiple groups, only the first assignment is kept.
• Invalid YAML keeps the previously applied settings.
• When the server is the source of truth, clients use the synced server YAML instead of their local file.

Config

[1 - General]

## If on, the configuration is locked and can be changed by server admins only. [Synced with Server]
# Setting type: Toggle
# Default value: On
# Acceptable values: Off, On
Lock Configuration = On

[2a - Player Diving]

## Comma-separated item prefab names that remain restricted in water. Everything not listed is allowed in water by default. Example: BowFineWood,ShieldBronzeBuckler. [Synced with Server]
# Setting type: String
# Default value: 
Water Equipment Blacklist = 

## Multiplier applied to vanilla stamina regeneration while swimming or diving in water. 0 matches vanilla swimming behavior (effective stamina regeneration stays at 0), 1 matches vanilla normal non-swimming stamina regeneration timing and rate. [Synced with Server]
# Setting type: Single
# Default value: 0.5
# Acceptable value range: From 0 to 2
Water Stamina Regen Rate = 0.5

## Depth in meters below the surface where extra swim stamina drain begins. [Synced with Server]
# Setting type: Single
# Default value: 3
# Acceptable value range: From 0 to 50
Water Depth Stamina Drain Start = 3

## Depth in meters below the surface where the maximum extra swim stamina drain multiplier is reached. [Synced with Server]
# Setting type: Single
# Default value: 30
# Acceptable value range: From 0.25 to 300
Water Depth Stamina Drain Full = 30

## Maximum multiplier applied to vanilla moving swim stamina drain at or below the full depth. [Synced with Server]
# Setting type: Single
# Default value: 1.5
# Acceptable value range: From 1 to 5
Water Depth Stamina Drain Max Multiplier = 1.5

## Final swim speed while swimming and holding the run key = base swim speed x [1 + (this value - 1) x (Swim skill level / 100)^1.5]. [Synced with Server]
# Setting type: Single
# Default value: 1.5
# Acceptable value range: From 1 to 3
Swim Run Speed Multiplier = 1.5

[3 - Performance]

## Single quality slider for underwater AI behavior. 0 = minimum CPU/minimum smoothness, 100 = maximum CPU/maximum smoothness. Internally adjusts route check cache time, steer cache time, cache cell size, and avoidance sample count. [Synced with Server]
# Setting type: Single
# Default value: 50
# Acceptable value range: From 0 to 100
Dive AI Quality = 50

Git

The player diving implementation includes code derived and modified from UnderTheSea
https://github.com/searica/UnderTheSea
https://github.com/sighsorry1029/DiveIn