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SkeletonModification2DCCDIK

Inherits: SkeletonModification2D < Resource < RefCounted < Object

A modification that uses CCDIK to manipulate a series of bones to reach a target in 2D.

Description

This SkeletonModification2D uses an algorithm called Cyclic Coordinate Descent Inverse Kinematics, or CCDIK, to manipulate a chain of bones in a Skeleton2D so it reaches a defined target.

CCDIK works by rotating a set of bones, typically called a “bone chain”, on a single axis. Each bone is rotated to face the target from the tip (by default), which over a chain of bones allow it to rotate properly to reach the target. Because the bones only rotate on a single axis, CCDIK can look more robotic than other IK solvers.

Note: The CCDIK modifier has ccdik_joints, which are the data objects that hold the data for each joint in the CCDIK chain. This is different from a bone! CCDIK joints hold the data needed for each bone in the bone chain used by CCDIK.

CCDIK also fully supports angle constraints, allowing for more control over how a solution is met.

Properties

Methods

Property Descriptions

int ccdik_data_chain_length = 0

• void set_ccdik_data_chain_length ( int value )

• int get_ccdik_data_chain_length ( )

The number of CCDIK joints in the CCDIK modification.

NodePath target_nodepath = NodePath("")

• void set_target_node ( NodePath value )

• NodePath get_target_node ( )

The NodePath to the node that is the target for the CCDIK modification. This node is what the CCDIK chain will attempt to rotate the bone chain to.

NodePath tip_nodepath = NodePath("")

• void set_tip_node ( NodePath value )

• NodePath get_tip_node ( )

The end position of the CCDIK chain. Typically, this should be a child of a Bone2D node attached to the final Bone2D in the CCDIK chain.

Method Descriptions

NodePath get_ccdik_joint_bone2d_node ( int joint_idx ) const

Returns the Bone2D node assigned to the CCDIK joint at joint_idx.

int get_ccdik_joint_bone_index ( int joint_idx ) const

Returns the index of the Bone2D node assigned to the CCDIK joint at joint_idx.

bool get_ccdik_joint_constraint_angle_invert ( int joint_idx ) const

Returns whether the CCDIK joint at joint_idx uses an inverted joint constraint. See set_ccdik_joint_constraint_angle_invert for details.

float get_ccdik_joint_constraint_angle_max ( int joint_idx ) const

Returns the maximum angle constraint for the joint at joint_idx.

float get_ccdik_joint_constraint_angle_min ( int joint_idx ) const

Returns the minimum angle constraint for the joint at joint_idx.

bool get_ccdik_joint_enable_constraint ( int joint_idx ) const

Returns whether angle constraints on the CCDIK joint at joint_idx are enabled.

bool get_ccdik_joint_rotate_from_joint ( int joint_idx ) const

Returns whether the joint at joint_idx is set to rotate from the joint, true, or to rotate from the tip, false. The default is to rotate from the tip.

void set_ccdik_joint_bone2d_node ( int joint_idx, NodePath bone2d_nodepath )

Sets the Bone2D node assigned to the CCDIK joint at joint_idx.

void set_ccdik_joint_bone_index ( int joint_idx, int bone_idx )

Sets the bone index, bone_idx, of the CCDIK joint at joint_idx. When possible, this will also update the bone2d_node of the CCDIK joint based on data provided by the linked skeleton.

void set_ccdik_joint_constraint_angle_invert ( int joint_idx, bool invert )

Sets whether the CCDIK joint at joint_idx uses an inverted joint constraint.

An inverted joint constraint only constraints the CCDIK joint to the angles outside of the inputted minimum and maximum angles. For this reason, it is referred to as an inverted joint constraint, as it constraints the joint to the outside of the inputted values.

void set_ccdik_joint_constraint_angle_max ( int joint_idx, float angle_max )

Sets the maximum angle constraint for the joint at joint_idx.

void set_ccdik_joint_constraint_angle_min ( int joint_idx, float angle_min )

Sets the minimum angle constraint for the joint at joint_idx.

void set_ccdik_joint_enable_constraint ( int joint_idx, bool enable_constraint )

Determines whether angle constraints on the CCDIK joint at joint_idx are enabled. When true, constraints will be enabled and taken into account when solving.

void set_ccdik_joint_rotate_from_joint ( int joint_idx, bool rotate_from_joint )

Sets whether the joint at joint_idx is set to rotate from the joint, true, or to rotate from the tip, false.