Class SkeletonIK3D

A node used to rotate all bones of a Skeleton3D bone chain a way that places the end bone at a desired 3D position.

Inheritance

SkeletonModifier3D

Node3D

Node

Object

SkeletonIK3D

Remarks

SkeletonIK3D is used to rotate all bones of a Skeleton3D bone chain a way that places the end bone at a desired 3D position. A typical scenario for IK in games is to place a character's feet on the ground or a character's hands on a currently held object. SkeletonIK uses FabrikInverseKinematic internally to solve the bone chain and applies the results to the Skeleton3D bones_global_pose_override property for all affected bones in the chain. If fully applied, this overwrites any bone transform from Animations or bone custom poses set by users. The applied amount can be controlled with the influence property.

# Apply IK effect automatically on every new frame (not the current)
skeleton_ik_node.start()

# Apply IK effect only on the current frame
skeleton_ik_node.start(true)

# Stop IK effect and reset bones_global_pose_override on Skeleton
skeleton_ik_node.stop()

# Apply full IK effect
skeleton_ik_node.set_influence(1.0)

# Apply half IK effect
skeleton_ik_node.set_influence(0.5)

# Apply zero IK effect (a value at or below 0.01 also removes bones_global_pose_override on Skeleton)
skeleton_ik_node.set_influence(0.0)

Properties

interpolation

Interpolation value for how much the IK results are applied to the current skeleton bone chain. A value of 1.0 will overwrite all skeleton bone transforms completely while a value of 0.0 will visually disable the SkeletonIK.

var interpolation : float

Property Value

float

Remarks

• void set_interpolation(float value)
• float get_interpolation

magnet

Secondary target position (first is target property or target_node) for the IK chain. Use magnet position (pole target) to control the bending of the IK chain. Only works if the bone chain has more than 2 bones. The middle chain bone position will be linearly interpolated with the magnet position.

var magnet : Vector3 = Vector3(0, 0, 0)

Property Value

Vector3

Remarks

• void set_magnet_position(Vector3 value)
• Vector3 get_magnet_position

max_iterations

Number of iteration loops used by the IK solver to produce more accurate (and elegant) bone chain results.

var max_iterations : int = 10

Property Value

int

Remarks

• void set_max_iterations(int value)
• int get_max_iterations

min_distance

The minimum distance between bone and goal target. If the distance is below this value, the IK solver stops further iterations.

var min_distance : float = 0.01

Property Value

float

Remarks

• void set_min_distance(float value)
• float get_min_distance

override_tip_basis

If true overwrites the rotation of the tip bone with the rotation of the target (or target_node if defined).

var override_tip_basis : bool = true

Property Value

bool

Remarks

• void set_override_tip_basis(bool value)
• bool is_override_tip_basis

root_bone

The name of the current root bone, the first bone in the IK chain.

var root_bone : StringName = &""

Property Value

StringName

Remarks

• void set_root_bone(StringName value)
• StringName get_root_bone

target

First target of the IK chain where the tip bone is placed and, if override_tip_basis is true, how the tip bone is rotated. If a target_node path is available the nodes transform is used instead and this property is ignored.

var target : Transform3D = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0)

Property Value

Transform3D

Remarks

• void set_target_transform(Transform3D value)
• Transform3D get_target_transform

target_node

Target node NodePath for the IK chain. If available, the node's current Transform3D is used instead of the target property.

var target_node : NodePath = NodePath("")

Property Value

NodePath

Remarks

• void set_target_node(NodePath value)
• NodePath get_target_node

tip_bone

The name of the current tip bone, the last bone in the IK chain placed at the target transform (or target_node if defined).

var tip_bone : StringName = &""

Property Value

StringName

Remarks

• void set_tip_bone(StringName value)
• StringName get_tip_bone

use_magnet

If true, instructs the IK solver to consider the secondary magnet target (pole target) when calculating the bone chain. Use the magnet position (pole target) to control the bending of the IK chain.

var use_magnet : bool = false

Property Value

bool

Remarks

• void set_use_magnet(bool value)
• bool is_using_magnet

Methods

get_parent_skeleton

Qualifiers: const

Returns the parent Skeleton3D node that was present when SkeletonIK entered the scene tree. Returns null if the parent node was not a Skeleton3D node when SkeletonIK3D entered the scene tree.

Skeleton3D get_parent_skeleton

is_running

Returns true if SkeletonIK is applying IK effects on continues frames to the Skeleton3D bones. Returns false if SkeletonIK is stopped or SkeletonIK3D.start was used with the one_time parameter set to true.

bool is_running

start(bool)

Starts applying IK effects on each frame to the Skeleton3D bones but will only take effect starting on the next frame. If one_time is true, this will take effect immediately but also reset on the next frame.

void start(bool one_time)

Parameters

one_time bool

stop

Stops applying IK effects on each frame to the Skeleton3D bones and also calls clear_bones_global_pose_override to remove existing overrides on all bones.

void stop