springBone

import { Vrm } from "@hmcs/sdk";

vrm.springBone(chainId) returns a single spring bone chain by its entity ID.

const { chains } = await character.springBones();
const chain = await character.springBone(chains[0].entity);
console.log(`Stiffness: ${chain.props.stiffness}`);
console.log(`Drag: ${chain.props.dragForce}`);

Returns a SpringBoneChain object. Use springBones to list all chains and find the chain ID you want.