IKHandler

Description

The IKHandler class manages Inverse Kinematics (IK) for character limbs and head. It provides smooth transitions for IK constraints, allowing characters to naturally interact with objects in the environment, such as looking at points of interest, placing hands on objects, or properly placing feet on surfaces.

Namespace

Universe.Character

Enums

IKNode

Defines the character body parts that can be controlled with IK.

Value	Description
Head	The character’s head/neck
LeftFoot	The character’s left foot
RightFoot	The character’s right foot
LeftHand	The character’s left hand
RightHand	The character’s right hand

Properties

Property	Type	Description
character	Character	Reference to the character to apply IK to
node	IKNode	The IK node/body part to control
positionWeigth	float	Strength of the position constraint (0-1, default: 1)
rotationWeight	float	Strength of the rotation constraint (0-1, default: 1)
target	UniObject	The target object for the IK constraint
setOnStart	bool	Whether to set the IK constraint automatically on start (default: true)
delay	float	Time in seconds for smooth transitions (default: 0.5)

Methods

OnStart

void OnStart()

Called when the script starts. Sets up the IK constraint if setOnStart is true.

SetIK

void SetIK()

Enables the IK constraint and transitions to full weight over the specified delay time.

ResetIK

void ResetIK()

Transitions the IK constraint weights to zero over the specified delay time.

OnUpdate

void OnUpdate()

Called every frame. Handles the smooth transition of IK weights.

Example Usage

// Make a character look at an object of interest
IKHandler headIK = new IKHandler();
headIK.character = playerCharacter;
headIK.node = IKNode.Head;
headIK.target = interestingObject;
headIK.positionWeigth = 0.8; // Not full constraint
headIK.rotationWeight = 1.0; // Full rotation constraint
headIK.delay = 0.3; // Quick transition

// Make a character place hand on object
IKHandler handIK = new IKHandler();
handIK.character = npcCharacter;
handIK.node = IKNode.RightHand;
handIK.target = doorHandle;
handIK.setOnStart = false; // Don't set immediately
handIK.delay = 1.0; // Slow, natural transition

// Later, when character should grab the handle:
handIK.SetIK();

// And when they should let go:
handIK.ResetIK();

Implementation Details

The IK system uses the character’s built-in IK capabilities through the Character.SetIKState(), Character.SetIKGoal(), and Character.SetIKWeights() methods
The transition weights are smoothly interpolated over the specified delay time
A value of -1 for targetValue will completely disable IK
The actual IK implementation details are handled in the Character class

Use Cases

Characters looking at points of interest or other characters
Hand placement for interaction with objects (grabbing, touching)
Foot placement on uneven terrain
Complex animations like climbing, leaning, or reaching
Procedural animation adjustments

Notes

For IK to work, the character model must have a proper rigging that supports IK
Setting appropriate weight values is important for natural-looking results
Multiple IK handlers can be used on different nodes of the same character
For complex IK scenarios, consider implementing a custom solution with greater control

Works with Character.cs for IK functionality
References the IKNode enum for target body parts

Dependencies

Requires a properly set up Character instance
Uses Time.GameTime() for timing
Uses Math functions for interpolation