[name]

A solver for IK with `CCD Algorithm`.

[name] solves Inverse Kinematics Problem with CCD Algorithm. [name] is designed to work with [page:SkinnedMesh] but also can be used with [page:MMDLoader] or [page:GLTFLoader] skeleton.

Code Example


		let ikSolver;

		//
		// Bones hierarchy:
		//
		//   root
		//     ├── bone0
		//     │    └── bone1
		//     │          └── bone2
		//     │                └── bone3
		//     └── target
		//
		// Positioned as follow on the cylinder:
		//
		//        o      <- target      (y =  20)
		//        
		//   +----o----+ <- bone3       (y =  12)
		//   |         |
		//   |    o    | <- bone2       (y =   4)
		//   |         |
		//   |    o    | <- bone1       (y =  -4)
		//   |         |
		//   +----oo---+ <- root, bone0 (y = -12)
		//

		let bones = []

		// "root"
		let rootBone = new Bone();
		rootBone.position.y = -12;
		bones.push( rootBone );

		// "bone0"
		let prevBone = new Bone();
		prevBone.position.y = 0;
		rootBone.add( prevBone );
		bones.push( prevBone );

		// "bone1", "bone2", "bone3"
		for ( let i = 1; i <= 3; i ++ ) {
			const bone = new Bone();
			bone.position.y = 8;
			bones.push( bone );
			
			prevBone.add( bone );
			prevBone = bone;
		}

		// "target"
		const targetBone = new Bone();
		targetBone.position.y = 24 + 8
		rootBone.add( targetBone );
		bones.push( targetBone );

		//
		// skinned mesh
		//

		const mesh = new SkinnedMesh( geometry,	material );
		const skeleton = new Skeleton( bones );

		mesh.add( bones[ 0 ] ); // "root" bone
		mesh.bind( skeleton );

		//
		// ikSolver
		//

		const iks = [
			{
				target: 5, // "target"
				effector: 4, // "bone3"
				links: [ { index: 3 }, { index: 2 }, { index: 1 } ] // "bone2", "bone1", "bone0"
			}
		];
		ikSolver = new CCDIKSolver( mesh, iks );

		function render() {
			ikSolver?.update();
			renderer.render( scene, camera );
		}

Examples

[example:webgl_animation_skinning_ik]
[example:webgl_loader_mmd]
[example:webgl_loader_mmd_pose]
[example:webgl_loader_mmd_audio]

Constructor

[name]( [param:SkinnedMesh mesh], [param:Array iks] )

[page:SkinnedMesh mesh] — [page:SkinnedMesh] for which [name] solves IK problem.
[page:Array iks] — An array of [page:Object] specifying IK parameter. target, effector, and link-index are index integers in .skeleton.bones. The bones relation should be "links[ n ], links[ n - 1 ], ..., links[ 0 ], effector" in order from parent to child.

[page:Integer target] — Target bone.
[page:Integer effector] — Effector bone.
[page:Array links] — An array of [page:Object] specifying link bones.
- [page:Integer index] — Link bone.
- [page:Vector3 limitation] — (optional) Rotation axis. Default is undefined.
- [page:Vector3 rotationMin] — (optional) Rotation minimum limit. Default is undefined.
- [page:Vector3 rotationMax] — (optional) Rotation maximum limit. Default is undefined.
- [page:Boolean enabled] — (optional) Default is true.
[page:Integer iteration] — (optional) Iteration number of calculation. Smaller is faster but less precise. Default is 1.
[page:Number minAngle] — (optional) Minimum rotation angle in a step. Default is undefined.
[page:Number maxAngle] — (optional) Maximum rotation angle in a step. Default is undefined.

Creates a new [name].

Properties

[property:Array iks]

An array of IK parameter passed to the constructor.

[property:SkinnedMesh mesh]

[page:SkinnedMesh] passed to the constructor.

Methods

[method:CCDIKHelper createHelper]()

Return [page:CCDIKHelper]. You can visualize IK bones by adding the helper to scene.

[method:this update]()

Update IK bones quaternion by solving CCD algorithm.

[method:this updateOne]( [param:Object ikParam] )

Update an IK bone quaternion by solving CCD algorithm.

Source

[link:https://github.com/mrdoob/three.js/blob/master/examples/jsm/animation/CCDIKSolver.js examples/jsm/animation/CCDIKSolver.js]