SpringBone has bugs if fps is too high ,springBone will faster, otherwise slower.

[redcool]

//
//SpringBone.cs for unity-chan!
//
//Original Script is here:
//ricopin / SpringBone.cs
//Rocket Jump : http://rocketjump.skr.jp/unity3d/109/
//https://twitter.com/ricopin416
//
//Revised by N.Kobayashi 2014/06/20
// Revised by ken, 2019/9/19, fixed fps related issue.
//
using UnityEngine;
using System.Collections;

namespace UnityChan
{
public class SpringBone : MonoBehaviour
{
//次のボーン
public Transform child;

    //ボーンの向き
    public Vector3 boneAxis = new Vector3(-1.0f, 0.0f, 0.0f);
    public float radius = 0.05f;

    //各SpringBoneに設定されているstiffnessForceとdragForceを使用するか？
    public bool isUseEachBoneForceSettings = true;

    //バネが戻る力
    public float stiffnessForce = 0.01f;

    //力の減衰力
    public float dragForce = 0.4f;
    public Vector3 springForce = new Vector3(0.0f, -0.0001f, 0.0f);
    public SpringCollider[] colliders;
    public bool debug = true;
    //Kobayashi:Thredshold Starting to activate activeRatio
    public float threshold = 0.01f;
    private float springLength;
    private Quaternion localRotation;
    private Transform trs;
    private Vector3 currTipPos;
    private Vector3 prevTipPos;
    //Kobayashi
    private Transform org;
    //Kobayashi:Reference for "SpringManager" component with unitychan 
    private SpringManager managerRef;

	public void Awake()
	{
		trs = transform;
		localRotation = transform.localRotation;
		managerRef = GetComponentInParent<SpringManager>();

        
    }
    public void OnEnable()
    {
		//Kobayashi:Reference for "SpringManager" component with unitychan
		// GameObject.Find("unitychan_dynamic").GetComponent<SpringManager>();
	    

		springLength = Vector3.Distance (trs.position, child.position);
		currTipPos = child.position;
		prevTipPos = child.position;
    }

    /// <summary>
    /// Update by ken.
    /// alteration fps related to time related.
    /// </summary>
    public void UpdateSpring()
    {
        const float FORCE_SCALE = 1000f;
        const float SPEED_SCALE = 10;


        var toPrev = currTipPos - prevTipPos;
        var dt = Time.deltaTime;

        var force = trs.rotation * (boneAxis * stiffnessForce) * FORCE_SCALE;
        force += -toPrev * dragForce * FORCE_SCALE * dt;
        force += springForce * FORCE_SCALE * dt;

        prevTipPos = currTipPos;
        currTipPos += (toPrev + force *0.1f)* SPEED_SCALE * dt;


        currTipPos = trs.position + (currTipPos - trs.position).normalized * springLength;

        currTipPos = CheckColliders(currTipPos);

        var aimDir = trs.TransformDirection(boneAxis);
        var aimRot = Quaternion.FromToRotation(aimDir, currTipPos - trs.position);
        //trs.rotation = aimRot * trs.rotation;
        trs.rotation = Quaternion.Lerp(trs.rotation, aimRot * trs.rotation,managerRef.dynamicRatio);
    }

    Vector3 CheckColliders(Vector3 currTipPos)
    {
        for (int i = 0; i < colliders.Length; i++)
        {
            if (Vector3.Distance(currTipPos, colliders[i].transform.position) <= (radius + colliders[i].radius))
            {
                Vector3 normal = (currTipPos - colliders[i].transform.position).normalized;
                currTipPos = colliders[i].transform.position + (normal * (radius + colliders[i].radius));
                currTipPos = ((currTipPos - trs.position).normalized * springLength) + trs.position;
            }
        }
        return currTipPos;
    }

    private void OnDrawGizmos()
    {
        if (debug)
        {
            Gizmos.color = Color.yellow;
            Gizmos.DrawWireSphere(currTipPos, radius);
        }
    }
}

}