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Vrm.findBoneEntity()

Finds the entity ID of a specific bone within the VRM character's skeleton. This allows for precise manipulation of individual bones for advanced character control and positioning.

Parameters

  • bone (Bones) - The name of the bone to find

Returns

Promise<number> - The entity ID of the specified bone

Available Bones

The VRM standard defines the following bone names:

Core Bones

  • hips - Root bone of the skeleton
  • spine - Lower spine
  • chest - Upper chest/torso
  • neck - Neck connection
  • head - Head bone

Arm Bones

  • leftShoulder / rightShoulder - Shoulder joints
  • leftArm / rightArm - Upper arm bones
  • leftForeArm / rightForeArm - Lower arm bones
  • leftHand / rightHand - Hand bones

Leg Bones

  • leftUpLeg / rightUpLeg - Upper leg bones (thighs)
  • leftLeg / rightLeg - Lower leg bones (shins)
  • leftFoot / rightFoot - Foot bones

Examples

Basic Bone Access

import {Vrm, entities} from '@homunculus/sdk';

const character = await Vrm.spawn('characters::humanoid.vrm');

// Get head bone entity
const headEntity = await character.findBoneEntity('head');
const boneTransform = await entities.transform(headEntity);
console.log(`Head bone entity ID: ${headEntity}, transform: ${JSON.stringify(boneTransform)}`);

// Get hand bone entities
const leftHandEntity = await character.findBoneEntity('leftHand');
const rightHandEntity = await character.findBoneEntity('rightHand');

console.log(`Left hand: ${leftHandEntity}, Right hand: ${rightHandEntity}`);

Common Use Cases

Facial Animation

Manipulate head and neck bones for looking behaviors and expressions.

Gesture Control

Control arm and hand bones for pointing, waving, and other gestures.

Interactive Elements

Attach UI elements or effects to specific bones that move with the character.

Physics Simulation

Apply constraints and forces to bones for realistic movement.

Accessibility Features

Highlight or manipulate specific bones for educational or debugging purposes.