Armature

Source (.js)Source (.d.ts)

Introduction

vtkArmature manages a hierarchical collection of bones that define a skeletal rig for animation. It stores per bone local, world, and skinning matrices directly, provides methods for traversing the bone hierarchy, computing world-space transforms from local matrices, and producing skinning matrices used by GPU rendering backends.

Methods

addBone

Add a bone to the skeleton.

Argument	Type	Required	Description
boneData	BoneData	Yes	Plain object with bone properties.

computeSkinningMatrices

Compute skinning matrices. skinningMatrix[i] = worldMatrix[i] * inverseBindMatrix[i]. Uses internal worldMatrices and writes to internal skinningMatrices.

computeWorldMatrices

Compute world matrices from local matrices by traversing the bone hierarchy. Uses internal localMatrices and writes to internal worldMatrices.

evaluatePose

Evaluate animation clip at a given time: compose TRS per bone from rest pose overridden by animated tracks, then compute world and skinning matrices.

Argument	Type	Required	Description
clip		Yes	The animation clip to evaluate.
time		Yes	The current time.

extend

Method used to decorate a given object (publicAPI+model) with vtkArmature characteristics.

Argument	Type	Required	Description
publicAPI		Yes	object on which methods will be bounds (public)
model		Yes	object on which data structure will be bounds (protected)
initialValues	IArmatureInitialValues	No	(default: {})

getBone

Get a bone by index.

Argument	Type	Required	Description
index	number	Yes	The bone index.

getBoneIndexByName

Get a bone index by name.

Argument	Type	Required	Description
name	string	Yes	The bone name.

getBoneName

Get the name of a bone by index.

Argument	Type	Required	Description
index	number	Yes	The bone index.

getBones

Get all bones in the skeleton.

getChildrenIndices

Get all children indices for a bone.

Argument	Type	Required	Description
index	number	Yes	The bone index.

getInverseBindMatrix

Get the inverse bind matrix for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

getLocalMatrices

Get the raw local matrices array (boneCount * 16 floats).

getLocalMatrix

Get the local matrix for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

getLocalRestMatrix

Compose the local rest matrix from TRS for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

getLocalRestRotation

Get the local rest rotation for a bone (quaternion [x, y, z, w]).

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

getLocalRestScale

Get the local rest scale for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

getLocalRestTranslation

Get the local rest translation for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

getNodeId

Get the node ID for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

getNumberOfBones

Get the number of bones in the skeleton.

getParentIndex

Get the parent index for a bone.

Argument	Type	Required	Description
index	number	Yes	The bone index.

getRootBoneIndices

Get all root bone indices (bones with parentIndex === -1).

getRootTransform

Get the root transform applied to root bones.

getSkinningMatrices

Get the raw skinning matrices array (boneCount * 16 floats).

getSkinningMatrix

Get the skinning matrix for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

getWorldMatrices

Get the raw world matrices array (boneCount * 16 floats).

getWorldMatrix

Get the world matrix for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.

insertBone

Insert a bone at a specific index.

Argument	Type	Required	Description
index	number	Yes	The index to insert at.
boneData	BoneData	Yes	Plain object with bone properties.

newInstance

Method used to create a new instance of vtkArmature.

Argument	Type	Required	Description
initialValues	IArmatureInitialValues	No	for pre-setting some of its content

removeBone

Remove a bone at a specific index.

Argument	Type	Required	Description
index	number	Yes	The index to remove.

setInverseBindMatrix

Set the inverse bind matrix for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.
matrix	Float32Array or Array[number]	Yes	The 4x4 inverse bind matrix.

setLocalMatrix

Set the local matrix for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.
matrix	Float32Array or Array[number]	Yes	The 4x4 local matrix.

setParentIndex

Set the parent index for a bone and update rootBoneIndices accordingly.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.
parentIndex	number	Yes	The parent bone index (-1 for root).

setRootTransform

Set the root transform applied to root bones.

Argument	Type	Required	Description
transform	Nullable<Float32Array>	Yes	The root transform matrix (mat4).

setSkinningMatrix

Set the skinning matrix for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.
matrix	Float32Array or Array[number]	Yes	The 4x4 skinning matrix.

setWorldMatrix

Set the world matrix for a bone.

Argument	Type	Required	Description
boneIndex	number	Yes	The bone index.
matrix	Float32Array or Array[number]	Yes	The 4x4 world matrix.