为什么当角色在爬楼梯的时候，如果停止移动角色，他就会慢慢地从楼梯上下来？

Question

角色(玩家)有Capsule Collider , Rigid body , Character Controller.这是角色(玩家)检查器设置的截图。

这是角色控制器的脚本。

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CharacterController : MonoBehaviour
{
    public float moveSpeed = 10.0f;
    public float jumpForce = 2.0f;

    void Start()
    {

    }

    // Update is called once per frame
    void Update ()
    {
        float translatioin = Input.GetAxis("Vertical") * moveSpeed;
        float straffe = Input.GetAxis("Horizontal") * moveSpeed;
        translatioin *= Time.deltaTime;
        straffe *= Time.deltaTime;

        transform.Translate(straffe, 0, translatioin);

        if (Input.GetKeyDown("escape"))
        {
            Cursor.lockState = CursorLockMode.None;
        }

        transform.Translate(0, jumpForce * Input.GetAxis("Jump") * Time.deltaTime, 0);
    }
}

角色(玩家)有一个主摄像头的子代：摄像头检查器的截图。

脚本Drag Rigidbody，使对象能够被拖动。

using System;
using System.Collections;
using UnityEngine;

namespace UnityStandardAssets.Utility
{
    public class DragRigidbody : MonoBehaviour
    {
        public bool useMouseHoldDown = true;

        [SerializeField] private Camera mainCamera;

        const float k_Spring = 50.0f;
        const float k_Damper = 5.0f;
        const float k_Drag = 10.0f;
        const float k_AngularDrag = 5.0f;
        const float k_Distance = 0.2f;
        const bool k_AttachToCenterOfMass = false;

        private SpringJoint m_SpringJoint;
        private bool isDragging;

        private void Awake()
        {
            if (!mainCamera) mainCamera = GetComponent<Camera>();
            if (!mainCamera) mainCamera = Camera.main;
        }

        private void Update()
        {
            if (!Input.GetMouseButtonDown(0) || isDragging) return;

            // Make sure the user pressed the mouse down
            if (!Input.GetMouseButtonDown(0))
            {
                return;
            }

            // We need to actually hit an object
            RaycastHit hit = new RaycastHit();
            if (
                !Physics.Raycast(mainCamera.ScreenPointToRay(Input.mousePosition).origin,
                                 mainCamera.ScreenPointToRay(Input.mousePosition).direction, out hit, 100,
                                 Physics.DefaultRaycastLayers))
            {
                return;
            }
            // We need to hit a rigidbody that is not kinematic
            if (!hit.rigidbody || hit.rigidbody.isKinematic)
            {
                return;
            }

            if (!m_SpringJoint)
            {
                var go = new GameObject("Rigidbody dragger");
                Rigidbody body = go.AddComponent<Rigidbody>();
                m_SpringJoint = go.AddComponent<SpringJoint>();
                body.isKinematic = true;
            }

            m_SpringJoint.transform.position = hit.point;
            m_SpringJoint.anchor = Vector3.zero;

            m_SpringJoint.spring = k_Spring;
            m_SpringJoint.damper = k_Damper;
            m_SpringJoint.maxDistance = k_Distance;
            m_SpringJoint.connectedBody = hit.rigidbody;

            StartCoroutine("DragObject", hit.distance);
        }


        private IEnumerator DragObject(float distance)
        {
            isDragging = true;

            var oldDrag = m_SpringJoint.connectedBody.drag;
            var oldAngularDrag = m_SpringJoint.connectedBody.angularDrag;
            m_SpringJoint.connectedBody.drag = k_Drag;
            m_SpringJoint.connectedBody.angularDrag = k_AngularDrag;

            if (useMouseHoldDown == true)
            {
                while (Input.GetMouseButton(0))
                {
                    var ray = mainCamera.ScreenPointToRay(Input.mousePosition);
                    m_SpringJoint.transform.position = ray.GetPoint(distance);
                    yield return null;
                }
            }
            else
            {
                while (!Input.GetMouseButton(0))
                {
                    var ray = mainCamera.ScreenPointToRay(Input.mousePosition);
                    m_SpringJoint.transform.position = ray.GetPoint(distance);
                    yield return null;
                }
            }
            if (m_SpringJoint.connectedBody)
            {
                m_SpringJoint.connectedBody.drag = oldDrag;
                m_SpringJoint.connectedBody.angularDrag = oldAngularDrag;
                m_SpringJoint.connectedBody = null;
            }

            isDragging = false;
        }
    }
}

在截图中，有些脚本只是为了测试而被禁用，但即使如此，玩家也在向下移动，如果不是一直用W键把他移上去的话。当释放W键时，玩家不是掉下来，而是从楼梯上往下移动。

当拖动一个物体时也会出现问题，例如3D立方体，如果我拖动立方体，然后将鼠标光标快速移动，就会将玩家用力推向某个方向，直到玩家慢慢停下来。我想问题出在FPSController的刚体上，但不确定是什么。

Answer 1

只是一个观察。Coroutines应该返回新的WaitForFixedUpdate()，因为物理学应该在FixedUpdate()循环中运行。